JP7286223B1 - Boundary layer control device, boundary layer control method, wind tunnel test device, and vehicle running simulation method - Google Patents

Abstract

A boundary layer control device and a wind tunnel test capable of accurately simulating the wind speed distribution and/or flow direction on the underside and floor of a running vehicle and/or on the back of the rear of the vehicle using a stationary vehicle in a wind tunnel facility. Provide equipment. A vehicle V is covered so that a boundary layer of a jet stream MF generated in a space between a vehicle lower surface and a floor FL can be sucked in when a jet stream generated in a wind tunnel T is blown onto the vehicle. A boundary layer suction surface 12 is provided on the floor surface FL, and a suction duct 14 facing the boundary layer suction surface 12 is provided below the floor surface FL. a suction means 18 for sucking the boundary layer through the suction means 18 and a suction amount adjusting means 20 for adjusting the suction amount of the boundary layer sucked by the suction means 18; and a static pressure distribution adjusting means capable of adjusting the static pressure distribution in the longitudinal direction of the vehicle in the space between the vehicle bottom surface and the floor surface FL, which is generated when the space between them flows in the longitudinal direction of the vehicle. boundary layer control device 10. [Selection diagram] Fig. 1

Description

The present invention is a boundary layer control device and a wind tunnel test device that can accurately simulate the wind speed distribution and/or flow direction on the underside and floor of a running vehicle and on the back of the rear of the vehicle using a stationary vehicle in a wind tunnel facility. and a method for simulating running of a vehicle.

2. Description of the Related Art Conventionally, circulating wind tunnel facilities or windsock wind tunnel facilities used for aerodynamic experiments simulating natural wind have been used for testing the wind speed distribution of vehicles such as automobiles.
In more detail, by generating a jet stream in the wind tunnel and ejecting it from the outlet of the wind tunnel toward the stationary vehicle in the measurement room outside the wind tunnel, the main stream air (steady flow rate) is generated during driving. It is designed to simulate the wind speed distribution around the vehicle.
In this case, the jet stream generated in the longitudinal direction of the vehicle in the wind tunnel simulates the wind velocity to which the vehicle is subjected while it is running, and is a parallel flow. flows in the front-rear direction.
However, in the jet stream that blows out from the outlet, a boundary layer with a delayed wind speed is generated along the floor surface due to the resistance between the main layer and the floor surface, in addition to the main layer due to the mainstream air. Therefore, when testing the wind speed distribution of a vehicle, it will be affected by the boundary layer.
Here, the boundary layer refers to a layer in a range where the velocity of the mainstream air flow near the floor surface changes rapidly from the floor surface to the flow velocity of the mainstream air. , refers to the layer where the flow velocity is reduced to 99% or less.
In order to reduce the influence of such a boundary layer, for example, as shown in Patent Document 1, a boundary layer suction device is provided in the measurement section of a wind tunnel test apparatus.

This boundary layer suction device was designed to reduce the influence of the boundary layer by sucking the jet stream from the floor surface on the upstream side of the actual vehicle provided in the measurement section and discharging it into the atmosphere. More specifically, the boundary layer suction device includes, in the measurement section, a suction port that sucks the jet stream into the floor surface of the measurement section on the upstream side of the actual vehicle, which is the test object, and a suction duct that feeds the sucked jet stream. , and a suction pump that draws in the jet stream.
With such a configuration, the boundary layer generated by the jet stream blown out from the outlet is sucked in the direction perpendicular to the flow direction of the jet stream blown out from the outlet, sucked by the suction pump through the suction duct, and discharged as exhaust air. By doing so, it was possible to test the wind speed distribution of the test object while suppressing the influence of the boundary layer.

However, when the flow of the jet stream that has flowed into the suction port is turned, stagnation pressure is generated by the flow of the jet stream being turned, and this stagnation pressure causes the flow of the jet stream to turn in the mainstream direction of the jet stream. Since the static pressure on the wake side increases, the flow in the mainstream direction of the jet stream blown out from the outlet is obstructed, resulting in a problem of wind speed reduction.

In this respect, for example, in Patent Document 2, it is difficult to uniformly eliminate the boundary layer on the ground plate with a device that blows and sucks with a nozzle, while a device that uses a moving belt has a high-speed wind tunnel. Since the test is impossible, the upper surface of the ground plate that simulates the ground installed in the wind tunnel and arranged almost parallel to the wind tunnel airflow is used as a wind tunnel ground simulation device. below the porous surface is provided with a chamber divided in the flow direction of the wind tunnel airflow, the chamber is connected to a suction pump through a suction duct, and between the chamber and the suction duct is provided with a plurality of valves for setting the flow rate of suction from each chamber, and the opening of the valves is set by a valve controller according to instructions from a computer.
In Patent Document 2, according to such a wind tunnel ground simulator, the boundary layer that develops on the ground plate through a large number of micropores on the porous surface of the ground plate is uniformly and , can be effectively sucked, can eliminate the influence of the boundary layer on the ground plate in wind tunnel tests, and can accurately simulate conditions such as flight of aircraft and running of vehicles. ing.
However, Patent Document 2 describes the significance of dividing the chambers in the direction of the wind tunnel airflow in uniformly and effectively sucking the boundary layer that develops on the ground plate, and/or The significance of the porous surface provided with a large number of micropores has not necessarily been clarified.

In this respect, for example, as shown in Patent Document 3, boundary layer control that reduces the obstruction of the flow in the mainstream direction of the jet stream that blows out from the outlet due to the sucked jet stream and reduces the decrease in wind speed. An apparatus and wind tunnel test apparatus boundary layer are disclosed.
In this boundary layer control device, the jet stream is circulated by the blower through an annular continuous air passage, and when the jet stream is blown out to the measurement section through the outlet, the main air of the jet stream is generated on the floor interface side. A boundary layer control device having a suction duct that sucks in and discharges a boundary layer in a vertical axis direction with respect to the mainstream direction of the jet stream, wherein the stagnation pressure of the jet stream sucked into the suction duct is reduced to reduce the stagnation pressure of the jet stream. In order to reduce the obstruction of the flow in the mainstream direction of the airflow, there is a wind guide part formed on the upstream side of the intake duct that guides a part of the jet stream into the intake duct, and near the downstream edge of the intake port of the intake duct. By providing a curved portion or providing a flange on the downstream side of the suction port of the suction duct, the boundary layer generated on the floor interface side of the mainstream air of the jet stream is shifted in the vertical axis direction with respect to the mainstream direction of the jet stream. Since the stagnation pressure of the jet stream sucked into the suction duct that is sucked into and discharged from the air stream can be reduced, obstruction of the flow in the mainstream direction of the jet stream can be reduced.

However, such a boundary layer control device merely reduces the obstruction of the flow in the mainstream direction of the jet stream in relation to the suction of the boundary layer that occurs on the floor interface side immediately after the outlet of the wind tunnel. , the wind speed distribution and/or flow direction between the underside of the vehicle and the floor, or at the rear of the vehicle.

In other words, the boundary layer control device is simply installed in the immediate downstream portion of the wind tunnel outlet, that is, the upstream side of the vehicle body that is the object of the wind speed distribution measurement test, and the boundary layer is the boundary between the main layer of the jet stream and the floor surface. As long as it is caused by the resistance between the front and rear parts of the car body, the occurrence of a boundary layer is inevitable even when the main flow passes through the longitudinal length of the car body, which extends several meters from the front to the rear. Therefore, if a boundary layer control device is installed only in the area directly downstream of the wind tunnel outlet, the development of the boundary layer on the floor, which does not occur in actual driving, will cause the airflow (wind speed distribution and/or or flow direction) is obstructed.
In this case, if the boundary layer control device is similarly installed on the floor corresponding to the underside of the vehicle, the static pressure distribution between the underside of the vehicle and the floor is not taken into consideration. Uneven layer absorption occurs.
In addition to simply measuring the wind speed distribution around the vehicle, in order to simulate actual driving such as fuel consumption, electricity consumption (EV vehicle), air conditioner test, heat management test, snowstorm test, rain test, etc., accuracy around the running simulated vehicle is required. Such interruptions to the mainstream make reliable assessment difficult, where high wind speed distribution and/or flow direction reproduction is essential.
On the other hand, in order to simulate the blow-up phenomenon behind the rear part of a running vehicle, it is necessary to reproduce the vortices that can occur on the rear part of the vehicle. .

In relation to this point, the driving simulation is usually performed by placing the vehicle in a measurement room outside the wind tunnel, rotating the wheels by rotating dynamo rollers installed below the floor, and jetting from the front to the rear of the vehicle. This is done by running an air current to simulate the wind speed during running.
The dynamo roller is normally provided in a non-contact manner with respect to the opening so as to face upward from the opening provided on the floor of the wind tunnel, and a gap is inevitably provided between the opening and the peripheral edge of the dynamo roller. Inevitably, entrainment air currents drawn from the measurement room due to the rotation of the dynamo roller or due to the static pressure difference between the dynamo installation room and the space between the vehicle bottom surface and the floor surface, Entrained air flows out into the measurement chamber inevitably, and the entrained air flows through the openings in the floor and forms a diagonal flow in the space between the underside of the vehicle and the floor, similar to the jet stream in the wind tunnel. , in the longitudinal direction of the vehicle.
As a result, the jet stream in the wind tunnel is disturbed in the space, making it difficult to perform an accurate running simulation test.
Recently, the battery is installed under the vehicle to evaluate the heat dissipation from the radiator to the lower part of the vehicle and to evaluate the heat dissipation of the battery of the electric vehicle while driving as part of the electric fuel test. Therefore, it is important to conduct a heat radiation test using an air current flowing through the space between the underside of the vehicle and the floor.
Such a technical problem tends to become more conspicuous as the simulated running speed increases, because entrained air currents become stronger.
As described above, conventionally, when using a wind tunnel test facility, attention has been paid to sucking in the boundary layer generated near the floor. When an airflow flows, no attention is paid to the wind velocity unevenness and/or flow direction unevenness that occur in the longitudinal direction of the vehicle due to the suction of the boundary layer in the space. There is nothing that simulates the condition of the jet stream to the same condition as the running vehicle.

Japanese Utility Model Publication No. 1-29558 JP-A-06-213764 JP 2009-156695 A

In view of the above technical problems, an object of the present invention is to utilize a stationary vehicle in a wind tunnel facility to excessively increase the wind speed distribution and/or flow direction on the underside and floor of a running vehicle and on the rear rear surface of the vehicle. To provide a boundary layer control device and a wind tunnel test device that can be practically and accurately simulated without increasing costs.
In view of the above technical problems, an object of the present invention is to accurately determine the wind speed distribution and/or flow direction on the underside and floor of a running vehicle and on the rear rear surface of the vehicle by using a stationary vehicle in a wind tunnel facility. An object of the present invention is to provide a control method for a simulated boundary layer.

In order to achieve the above object, the boundary layer control device of the present invention includes:
When blowing a jet stream generated in a wind tunnel to a vehicle,
A boundary layer suction surface disposed above the vehicle so as to be covered by the vehicle is provided on the floor surface so as to be able to absorb the boundary layer of the jet stream generated in the space between the vehicle lower surface and the floor surface,
A suction duct facing the boundary layer suction surface is provided below the floor surface,
a suction means for sucking the boundary layer through the boundary layer suction surface; and a suction amount adjusting means for adjusting the suction amount of the boundary layer sucked by the suction means;
In addition, the static pressure distribution in the longitudinal direction of the vehicle in the space between the underside of the vehicle and the floor can be adjusted when the jet stream flows in the space between the underside of the vehicle and the floor in the longitudinal direction of the vehicle. It is configured to have distribution adjusting means.

According to the boundary layer control device having the above configuration, when the jet stream is blown toward the vehicle located downstream of the outlet in the wind tunnel, for example, by using the blower, the jet stream is , where a boundary layer occurs between the bottom surface of the vehicle and the floor surface, the boundary layer is sucked into the suction duct facing the boundary layer suction surface through the boundary layer suction surface arranged above so as to be covered by the vehicle. The boundary layer can be sucked by the suction means. In this case, the static pressure distribution adjusting means controls the bottom surface of the vehicle generated when the jet stream flows in the space between the bottom surface of the vehicle and the floor in the longitudinal direction of the vehicle. Since it is possible to adjust the static pressure distribution in the longitudinal direction of the vehicle in the space between Even though the boundary layer is sucked, it is possible to suppress deviation from the static pressure distribution in the longitudinal direction of the vehicle in the space between the underside of the vehicle and the floor surface that occurs during actual running due to the suction of the boundary layer. As a result, in the space between the underside of the vehicle and the floor, a different wind speed distribution and/or flow direction may occur in the front-to-rear direction of the vehicle from the actual running, or from inside the intake duct to the space between the underside of the vehicle and the floor. It is possible to suppress the backflow of the air, and thus it is possible to perform a precise test approximating the actual running using the running simulation vehicle.

The static pressure distribution adjusting means adjusts the static pressure in the space between the vehicle bottom surface and the floor surface when the jet stream flows in the vehicle front-back direction in the space between the vehicle bottom surface and the floor surface, and the It is preferable to have a static pressure difference adjusting means capable of adjusting a static pressure difference from the static pressure in the suction duct.
Also, the static pressure difference adjusting means preferably has means for adjusting the static pressure in the suction duct below the floor surface with respect to the static pressure in the space between the vehicle bottom surface and the floor surface.
Further, the static pressure difference adjusting means preferably has means for adjusting the static pressure in the space between the vehicle bottom surface and the floor surface with respect to the static pressure in the suction duct below the floor surface.
Furthermore, the static pressure difference adjusting means is a partition plate extending across the width direction of the boundary layer suction surface to divide the suction duct into a plurality of regions, whereby the suction duct is divided into a plurality of regions in the front and rear of the vehicle. divided into multiple areas in the direction of
It is preferable that the boundary layer suction amount in each region is adjusted by the suction amount adjusting means according to the area of the divided boundary layer suction surface determined according to the position of the partition plate in the longitudinal direction of the vehicle.

In addition, the static pressure difference adjusting means preferably has a resistor provided on the boundary layer suction surface that forms a resistance to the suction jet stream.
Further, the resistor is preferably a porous body, and resistors having different resistance coefficients are laminated to reduce the unevenness of the suction air velocity distribution and/or the unevenness in the flow direction on the boundary layer suction surface.
Furthermore, the suction duct preferably has a suction pipe connected to the suction means, and the suction pipe is preferably provided with a damper.
Furthermore, it is preferable to further include stagnation pressure reducing means for reducing the stagnation pressure of the jet stream sucked into the suction duct.

In addition, a driving simulation device is placed on the floor below each wheel,
The driving simulation device includes an opening provided on the floor,
A cylindrical dynamo roller provided rotatably in a non-contact manner with respect to the opening;
a rotational drive means for rotationally driving the dynamo roller about the central axis of the cylinder;
The dynamo roller is arranged so that the central axis of the cylinder is located below the floor surface,
The dynamo roller is rotationally driven with the wheel of the vehicle placed on the outer peripheral surface facing the opening of the dynamo roller, thereby simulating the running of the vehicle,
The boundary layer control device may be arranged on a floor surface facing the lower surface of the vehicle, excluding the opening.
Further, the boundary layer control device is provided so that the boundary layer suction surface is positioned at a predetermined position behind the opening of the dynamo roller on a floor surface facing the lower surface of the vehicle, and the boundary layer control device is provided with the Boundary layer suction means draws air current generated by rotation of the dynamo roller and/or static pressure difference between the dynamo installation room and the bottom surface of the vehicle and the floor surface to cause the dynamo roller and the opening to move from the dynamo installation room side. It may also serve as entrainment airflow suppressing means for suppressing entrainment airflow generated by air flowing in through the gap from reaching the space between the lower surface of the vehicle and the floor surface through the opening.

Furthermore, a second boundary layer control device is further provided immediately after the outlet of the wind tunnel,
The second boundary layer control device has a stagnation pressure reducing means for reducing the stagnation pressure of the jet stream sucked into the intake duct, thereby reducing the pressure on the underside of the vehicle and the floor before the jet stream is blown out to the vehicle. It is desirable to reduce the obstruction of the flow of the jetstream flowing between the surfaces.

In order to achieve the above object, the boundary layer control method of the present invention comprises:
When using the boundary layer control device according to claim 1 to blow out a jet stream generated in a wind tunnel toward a stationary vehicle placed in a measurement room outside the wind tunnel to simulate traveling,
measuring the thickness of the boundary layer generated in the vehicle installation area at the portion of the boundary layer suction surface corresponding to each of the regions while changing the velocity of the jet stream without arranging the vehicle;
adjusting the suction amount of the boundary layer in each region based on the measured thickness of the boundary layer;
The jet stream generated in the wind tunnel is blown out toward a stationary vehicle placed in a measurement room outside the wind tunnel to perform various tests on the vehicle.

measuring the static pressure distribution between the vehicle bottom surface and the floor surface at each position in the longitudinal direction of the vehicle and the static pressure in the suction duct;
and/or adjusting the resistance coefficient of each of the resistors while adjusting the intake air volume according to the wind speed of the jet stream,
Thereby, the static pressure in the suction duct is preferably lower than the static pressure between the underside of the vehicle and the floor.

Further, it is preferable that the boundary layer suction surface on the vehicle front side has a larger resistance coefficient than the boundary layer suction surface on the vehicle rear side and/or the vehicle center portion.
Further, it is preferable that the boundary layer suction surface on the vehicle rear side is set to have a smaller suction amount than the boundary layer suction surface on the vehicle front side and/or the vehicle center portion.

In order to achieve the above objects, the wind tunnel test apparatus of the present invention includes:
Having the boundary layer control device according to claim 1,
When blowing out the jet stream generated in the wind tunnel through the outlet toward the vehicle placed in the measurement room outside the wind tunnel,
It is configured such that the boundary layer generated on the floor side of the jet stream is sucked substantially vertically downward with respect to the floor surface.
Further, the wind tunnel is preferably of a circulation type or a windsock type.

In addition, the boundary layer control device may control the area between the front and rear wheels and/or between a pair of front wheels,
and/or between each front wheel and an edge of said boundary layer suction surface, and/or between a pair of rear wheels, and/or between each rear wheel and an edge of said boundary layer suction surface. is good.
Furthermore, the boundary layer control device may be further arranged in the region between the front end of the vehicle and the front wheels and/or in the region between the rear end of the vehicle and the rear wheels.
In addition, the partition plate is preferably adjustable in position in the longitudinal direction of the vehicle.
Further, it is preferable that the aperture ratio and/or the number of laminations of the resistor are adjusted for each of the regions.

In order to solve the above problems, the driving simulation method of the present invention includes:
By blowing a jet stream generated in a wind tunnel toward the vehicle, the boundary layer generated in the space between the bottom surface of the specific vehicle during running simulation and the floor surface is sucked in a predetermined amount using the floor surface as the boundary layer suction surface. a step of inhaling in quantity;
a step of measuring the longitudinal static pressure distribution in the space between the bottom surface and the floor surface of the specific vehicle during running simulation;
The boundary layer suction surface is divided in the front-rear direction so that the measured front-rear static pressure distribution approximates the actual front-rear static pressure distribution in the space between the lower surface and the running surface of the specific vehicle that is actually running. and coarsely adjusting the longitudinal static pressure distribution by adjusting a predetermined amount of suction for each of the divided boundary layer suction surfaces according to the area of the divided boundary layer suction surface,
As a result, the wind velocity and/or flow direction of the jet stream in the space between the underside and the floor of the specific vehicle during running simulation are approximated to those of actual running.
Furthermore, for each divided boundary layer suction surface, the vertical static pressure difference with the boundary layer suction surface as a boundary is adjusted by selecting the coefficient of resistance when passing through the divided boundary layer suction surface against the boundary layer suction air flow. finely adjusting the longitudinal static pressure distribution.
Also, the step of sucking the boundary layer may include the step of calculating the boundary layer thickness according to the jet stream velocity.

A first embodiment of a wind tunnel test apparatus equipped with a boundary layer control device and/or a driving simulation device of the present invention will be described in detail below with reference to FIGS. 1 to 6. FIG.
The wind tunnel test apparatus 100 includes a wind tunnel T in which a jet stream MF is generated, boundary layer control devices 10A and 10B provided in a measurement chamber 109 provided between an outlet 106 and an inlet 108 of the wind tunnel T, and a running simulation. Both the boundary layer control device 10 and/or the driving simulation device 34 are provided below the floor FL of the measurement room 109 .
As shown in FIG. 1, the wind tunnel test apparatus 100 is of a circulating type, and is provided with a fan (blower) 101 that supplies a jet stream MF in a wind tunnel T. The jet stream MF collected at an inlet (collector) is The fan 101 adjusts the wind speed, forcibly circulates the air through the continuous air passage 103 in a substantially annular shape, blows out the jet airflow MF to the measurement chamber 109 through the air outlet 106, and from the measurement chamber 109 through the suction port 108. The jet stream MF is collected, and the jet stream MF is again circulated through the air duct 103 . The wind speed at the blow-out port 106 is determined by the number of rotations of the fan 101 as the steady flow rate of the jet stream MF flowing through the air duct 103 .

Corner vanes 105 for changing the flow direction of the jet stream MF are provided at respective corners in the middle of the air duct 103, and an air cooling device (not shown) is provided upstream of the corner vanes 105 on the downstream side of the fan 101. A measuring chamber 109 having a measuring portion inside is arranged surrounding the suction port 106 and the blowing port 108 . In the measurement room 109, a vehicle V to be tested is placed, and a jet stream MF is sent toward the vehicle V to perform fuel consumption, electricity consumption (EV vehicle), air conditioner test, heat management test, Tests such as blizzard tests, rain tests, etc. are conducted.

The wind tunnel T has a measurement chamber 109 of a semi-open circulation type, and includes a measurement chamber 109 in which a vehicle V to be measured is installed, a rectification tunnel 102, a contraction tunnel 104, and an outlet opening to the measurement chamber 109. 106 and an inlet 108 opening to the measurement chamber 109. For example, the airflow generated by the fan 101 passes through the rectification cavity 102 and the contraction cavity 104, and flows from the outlet 106 opening to the measurement chamber 109 into the measurement chamber. 109 and into the inlet 108 of the inlet 107 .
The airflow blown by the fan 101 is measured by once decreasing the wind speed (dynamic pressure) of the entire airflow and increasing the pressure (static pressure) in the intermediate body, and then passing through the contraction tunnel. The required and sufficient air flow (air velocity) can be blown out from the outlet into the measurement chamber.
As will be described later, when simulating a stationary vehicle V running in the measurement chamber 109, a parallel air current flowing from the front to the rear of the vehicle V is simulated according to the set running speed. By adjusting the wind speed of the airflow with the fan 101 according to the set running speed, the running vehicle V can be simulated even though the vehicle V is stationary.

Next, the frame structure of the floor FL in the measurement room where the driving simulation device 34 is installed will be explained. A rectangular parallelepiped space is formed in the apparatus chamber, and a pair of dynamo rollers 38 and a dynamo are roughly provided in the space.

The ceiling constitutes a floor surface FL into which the vehicle V can directly drive, and is formed with openings 36 through which the upper parts of the peripheral surfaces of the pair of dynamo rollers 38 are exposed. The dynamo roller 38 and the dynamo are supported on the bottom surface and provided in the equipment chamber.

As a modification, the dynamo and the dynamo roller 38 may be supported by a bottom plate provided in the housing, provided in the apparatus chamber, and integrated with the housing. According to this, the dynamo and the dynamo roller 38 can be integrated as a unit by using the housing as an outer shell, and is stable as a whole. Therefore, the entire apparatus can be easily and safely transported integrally, and can be easily installed in a predetermined test room. In addition, in this embodiment, since the ceiling constitutes the floor FL, there is no need to provide a separate floor FL, and it is only necessary to install the device, so the installation cost can be reduced and the overall device space can be reduced. be able to.
The intake duct of the boundary layer control device, which will be described later, is also common to the traveling simulation device in that it is provided below the floor surface, and the frame structure is also the same as described above. The suction duct of the boundary layer control device and the later-described partition plate are most preferably made of stainless steel, but may be made of steel subjected to anti-corrosion treatment (hot-dip galvanization or painting).

Next, explaining the boundary layer control device, as shown in FIG.
A second boundary layer control device 10B is provided immediately downstream, and in both cases, the jet stream MF is forcibly circulated by a fan (blower) through an annularly continuous air passage, and is sent to the measurement section through the outlet. They are common in that they have a suction duct that sucks and discharges the boundary layer generated on the floor interface side by the mainstream air of the jet stream MF in the vertical axis direction with respect to the mainstream direction of the jet stream MF when blowing out the jet stream MF.
First, the second boundary layer control device 10B will be described. As shown in FIGS. 3 and 4,
The jet stream MF is sucked from the boundary layer suction surface 12 formed on the floor surface on the upstream side of the vehicle, and discharged into the atmosphere by the fan 29 through the suction pipe 26, thereby reducing the influence of the boundary layer. A wind guide (not shown) is provided to guide part of the airflow MF into the intake duct. The stagnation pressure of the jet stream MF sucked into the intake duct is reduced as a result of reducing the flow turning angle when the air stream MF is turned in the vertical axis direction with respect to the mainstream direction of the jet stream MF. Directional flow blockage may be reduced.
The second boundary layer control device 10B provided immediately after the outlet of the wind tunnel has stagnation pressure reducing means (not shown) for reducing the stagnation pressure of the jet stream MF sucked into the intake duct, thereby reducing the jet Before the airflow MF is blown out to the vehicle V, obstruction of the flow in the mainstream direction of the jet airflow MF may be reduced.
The suction duct 14 is configured by a recess provided in a floor skeleton structure whose upper surface configures the floor surface FL.

Next, for the first boundary layer control device 10A, a boundary layer suction surface 12 having a larger area than the lower surface LS of the vehicle V is provided on the floor surface FL. Note that the first boundary layer control device 10A, like the second boundary layer control device 10B, moves the air in the suction duct through the suction pipe 26 to the fan 2
9 are common in that they are released to the atmosphere.
The boundary layer suction surface 12 has a rectangular shape, and the vehicle V is provided with openings 36 below the pair of front wheels FW and the pair of rear wheels RW. The layer suction surface 12 is provided in a region other than the opening 36 on the floor surface FL facing the lower surface LS of the vehicle V. As shown in FIG.

A suction duct 14 facing the boundary layer suction surface 12 is provided below the floor surface FL,
The suction duct 14 is partitioned into a plurality of regions 16 in the longitudinal direction of the vehicle V,
Each region 16 has suction means 18 for sucking the boundary layer through the boundary layer suction surface 12 and suction amount adjustment means 20 for adjusting the suction amount of the boundary layer sucked by the suction means 18 . The amount of suction of the boundary layer is adjusted according to the area of the boundary layer suction surface 12 partitioned by the partition plate 22 and corresponding to each of a plurality of regions 16 (described later).

In the plurality of regions 16, adjacent regions 16 are partitioned by partition plates 22, and each of the plurality of regions 16 constitutes a rectangular parallelepiped space.
In a plurality of regions 16 , the partition plate extends across the width direction W of the boundary layer suction surface 12 .
The position of each partition plate 22 in the longitudinal direction of the vehicle may be determined according to the static pressure distribution in the longitudinal direction between the vehicle bottom surface and the floor surface, the required volume of each of the plurality of regions 16, or the length in the longitudinal direction of the vehicle. For example, when it is desired to precisely simulate the air flow between the underside of the vehicle and the floor surface in the running simulation state, the interval between the adjacent partition plates in the longitudinal direction of the vehicle is narrowed, and the number of partition plates 22 is reduced accordingly. You can increase it. In particular, since the static pressure in the area corresponding to the wheels between the lower surface LS and the floor surface FL of the vehicle V is lower than that in other areas, it is preferable to divide the area corresponding to the wheels by the partition plate 22 .

The boundary layer suction surface 12 is provided with a resistor 24 that forms a resistance to the suction jet stream MF.
For example, as the resistor 24, it is preferable to use a combination of a perforated ventilation body, particularly a perforated plate, with a different opening ratio. It is better to reinforce with In this case, it is preferable not to provide such a strength member in the direction perpendicular to the jet stream MF.
The resistors 24 are laminated with resistors 24 having different resistance coefficients, and the type and/or the number of layers of the resistors 24 are adjusted for each region 16 so that the lower surface LS and the floor of the vehicle V are adjusted in each region 16 . By varying the resistance coefficient of the resistor according to the static pressure distribution between the surface FL and the boundary layer suction surface 12 in each region, partial unevenness in the suction wind speed distribution is reduced.

The suction duct 14 has a suction pipe 26 which is communicatively connected to the suction means 18. The suction pipe 26 is provided with a damper 27, and the damper 27 is adjusted as usual to reduce the suction air flowing through the suction pipe 26. Adjustable flow rate.
The partitions and/or resistors 24 are movable in the fore-and-aft direction of the vehicle V so that the spacing between adjacent partitions in the fore-and-aft direction of the vehicle V of each of the plurality of regions 16 is adjustable.
As a result, the interval between adjacent partitions in the longitudinal direction of the vehicle V in each area 16 may be adjusted according to the purpose of the test, the vehicle type, variations in simulated running speed in the same vehicle type, and the like.
The suction means 18 may be a fan, and the suction amount adjusting means 20 may adjust the suction amount by an inverter (not shown) that controls the rotation speed of the fan.
Multiple regions 16 may share a fan, for example, multiple regions 16 as long as the combination with resistors 24 and/or dampers 27 allows adequate suction of the boundary layer in each region 16 . All may share a fan.

Static pressure distribution in the longitudinal direction of the vehicle in the space between the lower surface LS of the vehicle V and the floor when the jet stream MF flows in the longitudinal direction of the vehicle V The static pressure distribution adjusting means can adjust the static pressure difference in the space between the lower surface LS of the vehicle V and the floor surface and in the suction duct 14 below the floor surface. It further has a static pressure difference adjusting means 32 .

The static pressure difference adjusting means 32 includes a plurality of partition plates 22 partitioning the suction duct 14 in the longitudinal direction of the vehicle, and resistors 24 provided on the boundary layer suction surface 12 corresponding to each region of the suction duct 14 partitioned by the partition plates 22. configured to
In an actual running vehicle, the jet stream MF generates a static pressure distribution in the longitudinal direction in the space between the lower surface LS of the vehicle V and the floor surface. It deviates from the longitudinal static pressure distribution. More specifically, in each region partitioned by the partition plate 22, the wind velocity unevenness and/or flow direction unevenness of the suction airflow through the boundary layer suction surface 12 affects the front-back direction static pressure distribution in the space. , by adjusting the difference between the static pressure in the space between the lower surface LS of the vehicle V and the floor surface and the static pressure in the intake duct 14, the wind speed and/or flow direction unevenness of the intake airflow can be adjusted. to reduce
Therefore, static pressure distribution adjusting means is provided in order to approximate the static pressure distribution in the front-rear direction in the space between the lower surface LS of the vehicle V and the floor surface in the running simulation vehicle to that of actual running, The static pressure distribution adjusting means adjusts the static pressure in the space between the bottom surface LS of the vehicle V and the floor surface when the jet stream flows in the longitudinal direction of the vehicle V in the space between the bottom surface LS and the floor surface of the vehicle V. and the static pressure in the suction duct 14 below the floor surface. Or, it may be configured by laminating materials having the same resistance coefficient or different resistance coefficients.

When the resistors 24 having the same aperture ratio are used to stack a plurality of resistors 24, the overall aperture ratio can be adjusted by shifting the center of the hole of each resistor 24 and stacking them. In the case of using resistors 24 with different aperture ratios, a porous body with a large pore size and strength secured by its thickness may be laminated with a lightweight wire mesh with a small pore size.
In any case, in preparation for the case where the static pressure distribution in the space between the lower surface of the vehicle V and the floor surface FL differs depending on the vehicle type, the basic resistor 24 is fixedly installed and detachably installed as an adjustment resistor. Additional layers of body 24 may be used.

As a modification, the boundary layer control device 10 is provided so that the boundary layer suction surface is located at a predetermined position behind the opening 36 of the dynamo roller 38 on the floor surface FL facing the lower surface LS of the vehicle. The boundary layer suction means of the device 10 is forced to move the dynamo roller from the dynamo installation room side due to entrained airflow generated by the rotation of the dynamo roller 38 and/or the static pressure difference between the dynamo installation room and the lower surface LS and the floor surface FL of the vehicle V. It also serves as an entrained air current suppressing means for suppressing the entrained air current generated by the air flowing in through the gap between the opening 38 and the opening 36 from reaching the space between the lower surface LS of the vehicle V and the floor surface FL through the opening 36. good.

The boundary layer control method uses the above-described boundary layer control device 10 to blow out the jet stream MF generated in the wind tunnel toward a stationary vehicle V placed in the measurement chamber 109 outside the wind tunnel, and when simulating running,
a step of measuring the thickness of the boundary layer generated in the vehicle V installation area at the portion of the boundary layer suction surface 12 corresponding to each region 16 while changing the velocity of the jet stream MF without arranging the vehicle;
adjusting the drag coefficient and/or the amount of boundary layer suction in each region 16 based on the measured boundary layer thickness so as to reduce the suction wind speed unevenness at the boundary layer suction surface 12;
The jet stream MF generated in the wind tunnel is blown out toward the stationary vehicle V placed in the measurement chamber 109 outside the wind tunnel, and the wind speed distribution around the vehicle V is measured while adjusting the suction amount of the boundary layer in each region 16. and conduct various tests.
More specifically, the static pressure between the vehicle bottom surface and the floor surface FL at each position in the longitudinal direction of the vehicle V,
measuring the static pressure in the suction duct 14;
and/or adjusting the resistance coefficient of each of the resistors 22 while adjusting the intake air volume according to the wind speed of the jet stream MF,
Thereby, the static pressure in the suction duct 14 is made lower than the static pressure between the vehicle bottom surface and the floor surface FL.

Regarding the maximum amount of suction in the suction means, since the velocity gradient in the boundary layer is steep, the boundary layer thickness, the width of the boundary layer suction surface (in the width direction of the vehicle), and/or the main jet stream MF It may be set in consideration of the safety factor depending on the flow velocity.
When using a suction means having such a maximum suction capacity, in each region partitioned by the partition plate, the flow velocity of the suction air current on the boundary layer suction surface (face wind speed ) is determined, if the area of the boundary layer suction surface is too small, the flow velocity of the suction air flow becomes excessive, and as a result, the static pressure in the space between the vehicle undersurface and the floor surface corresponding to each region is As a result, it deviates from the static pressure field around the vehicle V during actual running. Therefore, it is advisable to secure the length of each region partitioned by the partition plate in the longitudinal direction of the vehicle to the extent that such an effect does not occur. preferable.

Further, it is preferable to set the flow resistance of the boundary layer suction surface 12 on the vehicle front side to be larger than that of the boundary layer suction surface 12 on the vehicle rear side and/or the vehicle center portion by selecting the resistor 24 . As a result, static pressure on the boundary layer suction surface 12 on the front side of the vehicle is lower than that on the rear side of the vehicle. Where a backflow occurs, it is possible to suppress such a backflow and reduce the suction wind speed unevenness in the longitudinal direction of the boundary layer suction surface 12 .
Further, the boundary layer suction surface 12 on the vehicle rear side is preferably set to have a smaller suction amount than the boundary layer suction surface 12 on the vehicle front side and/or the vehicle center portion. As a result, it is possible to easily reproduce the phenomenon in which the wind blows up at the rear portion of the vehicle V. FIG.

According to such a boundary layer control method, the thickness of the boundary layer is measured based on actual measurements in an actual test facility. Compared to determining the thickness, in actual equipment, the thickness of the boundary due to construction accuracy is thicker than in simulations and theoretical formulas, so it is possible to control the boundary layer more precisely. Depending on the test objectives used, the variation range of the jet stream MF velocity may be determined.

As described above, in the wind tunnel, when the jet stream MF generated in the wind tunnel is blown out through the outlet toward the vehicle V arranged in the measurement chamber 109 outside the wind tunnel, the main stream of the jet stream MF is generated on the floor surface FL side. The wind tunnel may be of a circulating type or a windsock type as long as the boundary layer can be sucked in substantially vertically downward with respect to the floor FL.

According to the boundary layer control device having the above configuration, when the jet stream MF is blown out toward the vehicle V located downstream of the outlet in the wind tunnel T, for example, by using the blower, the jet stream MF is Where a boundary layer is formed between the lower surface of the vehicle V and the floor surface FL with respect to the main stream, suction faces the boundary layer suction surface 12 through the boundary layer suction surface 12 arranged above so as to be covered by the vehicle. The boundary layer can be sucked into the duct 14 by suction means for sucking the boundary layer. Since it is possible to adjust the static pressure distribution in the longitudinal direction of the vehicle in the space between the vehicle undersurface and the floor surface FL when the jet airflow MF flows in the longitudinal direction, When flowing in the space in the longitudinal direction of the vehicle, the boundary layer in the vicinity of the floor surface is sucked in, but due to the suction of the boundary layer, the space between the vehicle undersurface and the floor surface FL is generated in the longitudinal direction of the vehicle during actual running. As a result, in the space between the vehicle bottom surface and the floor surface FL, a wind speed distribution and/or flow direction that differs from the actual running direction may occur in the longitudinal direction of the vehicle. , suction duct 14
It is possible to suppress backflow from the inside to the space between the vehicle undersurface and the floor surface FL. Become.

Next, details of the driving simulator 34 will be described with reference to FIG.
The driving simulation device 34 is installed below the floor FL of a measurement room 109 in which an air flow is caused by a wind tunnel T. In the measurement room 109, a vehicle V to be measured is installed, and the wheels WH of the stationary vehicle V are installed. It is configured to be rotationally driven by the driving simulation device 34 .
In the measurement room 109, a driving simulation device 34 is provided corresponding to each of the pair of front wheels FW and the pair of rear wheels RW (one of each is shown in the drawing). Using these driving simulators 34, various characteristics of the automobile advanced on the measurement chamber 109 are measured.

Each dynamo roller 38 is provided in a dynamo installation chamber below the floor FL, and a rotating shaft 13 provided on its central axis is rotatably supported by a bearing (not shown) provided on the bottom plate. there is A connecting shaft (not shown) is arranged coaxially between the two dynamo rollers 38, and is connected to the rotating shafts of the two dynamo rollers 38 by a coupling (not shown), whereby the two dynamo rollers 38 are integrated. rotatable.

The dynamo is a liquid-cooled drive source for rotating the dynamo rollers 38, and the input/output shaft (not shown) is coaxially arranged with the rotation axis of one of the dynamo rollers 38, and the locking disc (not shown) connected by A torque meter (not shown) is provided on the input/output shaft of the dynamo so that the torque on the input/output shaft can be detected.

The driving simulation device 34 arranges the wheel WH of the automobile advanced on the measurement room 109 on the dynamo roller 38 whose zenith is exposed from the opening 36 provided on the floor FL of the measurement room 109 and makes it run. , the dynamo applies torque to the wheels WH via the dynamo rollers 38, and the torque applied from the wheels WH is measured by a load cell (not shown).

As the driving simulator 34 according to the present embodiment, instead of using four driving simulators 34 each having one dynamo roller 38 and one dynamo, two dynamos each having one wheel WH mounted thereon are used. A running simulation device 34 having a roller 38 and one dynamo for rotationally driving the two dynamo rollers 38 may be used.
A solid bar-shaped centering pipe 35 is provided in the width direction W of the opening 36 directly below the upstream edge 24 and the downstream edge 28 of each opening 36 . When positioning the vehicle V in the measurement chamber 109, the wheels WH of the vehicle V are centered with respect to the corresponding openings 36 so that the corresponding dynamo rollers 38 It is used as a guideline so that it can be rotationally driven by

In the above-described driving simulator 34, the vehicle V is arranged in the measurement chamber 109 outside the wind tunnel T in a direction perpendicular to the central axis of the cylinder of the dynamo roller 38. A cylindrical dynamo roller configured to send a jet stream MF from the floor surface FL toward the rear, over a height from the floor FL to at least the vehicle height, and rotatably provided in a non-contact manner with respect to the opening 36 The dynamo roller 38 is arranged so that the central axis of the cylinder is positioned below the floor surface FL, and the dynamo roller 38 is rotated with the wheels WH of the vehicle V placed on the upper outer peripheral surface facing the opening 36 of the dynamo roller 38. By driving, the running of the vehicle V is simulated.

Furthermore, for each opening 36, the uppermost portion 23 of the upper outer peripheral surface of the dynamo roller 38 is set flush with the floor FL, and the entrained airflow generated by the rotation of the dynamo roller 38 and/or the dynamo installation room. Entrained air currents B1 and B2 generated by the inflow air from the dynamo installation room side due to the static pressure difference between the vehicle bottom surface LS and the floor surface FL flow through the opening 36 into the space between the vehicle V bottom surface LS and the floor surface FL. An entraining airflow suppressing means 21 for suppressing the airflow from reaching the gas is provided in the gap C between the opening 36 and the dynamo roller 38. - 特許庁
More specifically, the opening 36 has a rectangular shape, and the entrained airflow suppressing means 21 corresponds to the gap C between the upstream edge 24 of the opening 36 and the corresponding dynamo roller 38 and/or the downstream edge 28 of the opening 36. It is a flat plate arranged in each gap C between the dynamo roller 38

As shown in FIG. 5, the size of the opening 36 depends on the size of the dynamo roller 38 and is determined from the viewpoint of not contacting the dynamo roller 38. The directional length L is 600 mm to 700 mm, and the gap C between the dynamo roller 38 and the opening edge is typically 10 mm to 20 mm wide.
The material and size of the flat plate may be appropriately determined from the viewpoint of effectively suppressing the entrained air current by the entrained air current suppressing means 21. For example, the material is arbitrary as long as flexibility is ensured. The width of the opening 36 may be permanently fixed to the floor surface FL by extending the width of the opening 36, and the length of the vehicle V in the front-rear direction is determined by the upstream and downstream edges 24 and 28 of the opening 36, respectively. to the uppermost portion 23 are covered. If it is permanently fixed, when vehicle V passes above,
It must be thick enough to withstand. It should be noted that it may be of a detachable type instead of being permanently fixed.

The entrained air current is generated by the rotation of the dynamo roller 38 shown below, and/or the static pressure difference between the dynamo installation room where the dynamo roller 38 is accommodated and the vehicle bottom surface and the floor surface causes the air flow from the dynamo installation room side. There may be entrained air currents generated by the incoming air of .
In this case, as shown in FIG. 5, from the opening 36 of the dynamo roller 38 to the space between the lower surface LS and the floor surface FL of the vehicle V, the entrainment airflow B1 caused by the blown (inflow air) flow is , the flat plate 21A provided on the upstream edge 24 of the opening 36 is suppressed from extending into the space, while the lower surface LS of the vehicle V and the floor surface FL generated by the downward rotation of the dynamo roller 38 from the opening 36 It is possible to suppress the flat plate 21B provided at the downstream edge 28 of the opening 36 from being sucked into the entraining airflow B2 from the space between them.
A predetermined gap is provided between the peripheral edge of the dynamo roller 38 and the peripheral edge of the opening 36, and the static pressure difference between the dynamo installation room and the lower surface LS of the vehicle V and the floor surface FL causes inflow air from the dynamo installation room side. The entraining airflow generated by the airflow mainly reaches the space between the lower surface LS of the vehicle V and the floor surface FL through a predetermined gap.
In this case, the boundary layer suction surface 12 is located at a predetermined position behind the opening 36 of the dynamo roller 38 on the floor surface FL facing the lower surface LS of the vehicle V (see 12F and 12G in FIG. 13). The layer control device 10 is provided, and the boundary layer suction means 18 of the boundary layer control device 10 is controlled by the entrained airflow generated by the rotation of the dynamo roller 38 and/or between the dynamo installation room and the lower surface LS of the vehicle V and the floor surface FL. entrainment airflow suppressing means for suppressing entrainment airflow generated by inflowing air from the dynamo installation room side due to the static pressure difference of . preferable.
As shown in FIG. 13, the dynamo installation chamber corresponding to the opening 36 and the suction duct 14 corresponding to each of the boundary layer suction surfaces 12F and 12G are separated from each other without communication. The distance between the leading edge of each of 12F and 12G and the trailing edge of the opening 36 is preferably determined from the viewpoint that the boundary layer suction means 18 can also serve as the entrained airflow suppressing means, as described above.
For example, in the case of a test in which the rotation of the wheels FW is stopped, the dynamo roller 38 is not rotated, so entrained air currents due to the rotation of the dynamo roller 38 are not generated. Due to the static pressure difference between LS and FL, an entraining airflow is generated by the inflowing air from the dynamo installation room side, which has high static pressure, through the gap between the roller end surface of the dynamo roller 38 and the opening 36, and the lower surface LS of the vehicle V and the floor surface FL In this case, the boundary layer suction surfaces 12F and 12G function particularly effectively to suck the boundary layer between the lower surface LS of the vehicle V and the floor surface FL. In addition, it is possible to suck such inflow air into the suction duct 14, and to suppress the turbulence of the airflow between the lower surface LS of the vehicle V and the floor surface FL.

The action of the traveling simulation device 34 having the above configuration will be described below as a traveling simulation method using the traveling simulation device 34 .
Schematically, the driving simulation method using the driving simulation device 34 is as follows. placing and narrowing the gap C between the opening 36 and the periphery of the dynamo roller 38;
The traveling simulation stage of the vehicle V in which the wheels WH are rotated by the rotation of the dynamo rollers 38 while the jet stream MF is flowing from the front to the rear of the vehicle V in the wind tunnel T. It can be realized by the airflow suppressing means 21 .
In this case, the step of narrowing the gap is performed by means of the entrained airflow restraining means 21, which are detachable or movable, and which are positioned on the vehicle so that the wheels WH are positioned in the corresponding openings 36. When the vehicle V is moved on the floor FL, it is preferable to remove the entraining airflow suppressing means 21 or make it movable and install it after the vehicle V is moved.

More specifically, in the measurement room 109 outside the wind tunnel T, from the front to the rear of the vehicle V, while sending the jet stream MF over the height from the floor FL to at least the vehicle height, the dynamo roller 38 is measured. By rotating the dynamo roller 38 with the wheels WH of the vehicle V placed on the upper peripheral surface facing the opening 36, it is possible to simulate the traveling of the vehicle V by the stationary vehicle V.
At that time, an entrained air current is generated by the rotation of the dynamo roller 38, and/or an entrained air current is generated by the inflow air from the dynamo installation room side due to the static pressure difference between the dynamo installation room, the lower surface LS of the vehicle V, and the floor surface FL. is unavoidably generated, and the jet stream MF in the measurement chamber 109 outside the wind tunnel T is disturbed in the space between the lower surface LS of the vehicle V and the floor surface FL. By providing entrained airflow suppression means 21 in the gap C between the peripheral edge,
and/or by providing the boundary layer control device 10 such that the boundary layer suction surface 12 is located at a predetermined position behind the openings 36 of the dynamo rollers 38, such entraining airflow is directed through the openings 36 in the floor FL. , can be suppressed from reaching the space between the vehicle V lower surface LS and the floor surface FL, thereby simulating the wind speed generated according to the running of the vehicle V. is disturbed in the space between the underside LS of the vehicle V and the floor FL.

As a result, various tests such as fuel consumption, electricity consumption (EV car), air conditioner test, heat management test, snowstorm test, rain test, etc. that simulate actual driving can be performed in the space between the lower surface LS of the electric vehicle and the road surface. , entrainment airflow generated by the rotation of the dynamo roller 38 and/or entrainment airflow generated by the inflow air from the dynamo installation chamber side due to the static pressure difference between the dynamo installation chamber and the lower surface LS and the floor surface FL of the vehicle V It is possible to accurately simulate the airflow passing from the front to the rear of the vehicle V without turbulence and ensure the reliability of the heat dissipation test.
When the vehicle V is four-wheel drive, the dynamo rollers 38 are used to simultaneously rotate the front wheels FW and/or the rear wheels RW. Although it is preferable to apply the suppressing means 21, when the vehicle V is FF or FR, it is not necessary to use the dynamo roller 38 for the opening 36 corresponding to the non-driven rear wheel RW or front wheel FW. In the case of a test emphasizing the underfloor airflow of the vehicle V, the opening 36 and the dynamo roller 3
8 may be moved integrally, or the opening 36 may be covered.

As a modification, the entrained airflow suppressing means 21 is a brush 32 extending from each of the upstream side edge 24 and the downstream side edge 28 of the opening 36 toward the uppermost portion 23 of the wheel WH and the dynamo roller 38. It may be closely provided over the entire width direction W of the side edge.
As a further modification, the entrained airflow suppressing means 21 is supported using the floor frame structure that constitutes the floor surface FL, and extends from the lower surface LS level of the floor surface FL to the upper outer peripheral surface level of the dynamo roller 38 and the opening edge. An entrained airflow damming member having a damming surface extending along the extension direction may also be used.
As a further modified example, the entrained airflow suppressing means 21 is a suction pipe for sucking the entrained airflow B, which is supported using the floor frame structure that constitutes the floor surface FL, and is oriented so as to face the suction opening 36 on the upstream side. Yes, the suction opening 36 may be provided between the floor FL and the upper peripheral surface level of the dynamo roller 38 .
As a further modification, the entrained airflow suppressing means 21 is a damming plate that is supported using the floor frame structure that constitutes the floor surface FL and extends along the opposite side edge 26 of the opening 36. The edge may be set at the level of the floor surface FL, and the lower edge may be set in a range that does not contact the upper peripheral surface of the dynamo roller 38 .

As a further modification, the entrained airflow suppressing means 21 is supported using the floor frame structure that constitutes the floor surface FL, and includes an upper surface facing the floor surface FL, a lower curved surface facing the upper outer peripheral surface of the dynamo roller 38, and the floor. and a rear surface extending from the surface FL toward the upper outer peripheral surface of the dynamo roller 38, and extending along the downstream edge 28. The lower surface LS of the floor surface FL An upper ejector flow path may be formed between the upper surface of the ejector flow path forming member and a lower ejector flow path between the lower curved surface of the ejector flow path forming member and the upper outer peripheral surface of the dynamo roller 38 . In this case, the inclination and the length of the upper ejector flow path and the lower ejector flow path are determined from the viewpoint of effectively suppressing the entrained air flow by the entrained air flow suppressing means 21, so that the space inside the ejector causes a decrease in pressure and the outside air. It may be determined appropriately so as to draw in airflow B2 from the space between the lower surface LS of the vehicle V and the floor surface FL, which is generated by the downward rotation of the dynamo roller 38 from the opening 36. , it is possible to prevent the ejector passage forming member provided at the downstream edge 28 of the opening 36 from being sucked.

When the simulated running speed is set, the rotation speed of the dynamo roller and the jet stream speed to be generated in the wind tunnel are determined accordingly, and the thickness of the boundary layer is determined according to the jet stream speed, and boundary layer control is performed. While the amount of boundary layer suction by the device 10 is set, if the entrained airflow is generated by the rotation speed of the dynamo roller, the suction amount of the entrained airflow is determined according to the rotation speed of the dynamo roller, and the dynamo is installed. In the case of an entrainment airflow generated by the inflow air from the dynamo installation room side due to the static pressure difference between the room, the vehicle lower surface LS and the floor surface FL, it is provided between the pair of front wheels FW as determined by the jet airflow speed Since the boundary layer suction amount in the region 16 or the region 16 provided between the pair of rear wheels RW is likely to be affected by the air flow entrained by the traveling simulation device 34 adjacent in the longitudinal direction of the vehicle, the set dynamo roller The position of the partition plate that partitions each area in the vehicle front-rear direction may be finely adjusted according to the number of revolutions of -.

A second embodiment of the present invention will be described below with reference to FIG. In the following description, constituent elements similar to those of the first embodiment are given the same reference numerals, and the description thereof is omitted. Characteristic portions of the present embodiment will be described in detail below.
The feature of the second embodiment of the present invention resides in the first boundary layer control device 10A. In the first embodiment, the second boundary layer control device 10B, which is provided immediately downstream of the wind tunnel outlet 106, is arranged in the measurement section. Although it is independent from the first boundary layer control device 10A provided below the vehicle, in this embodiment, the first boundary layer control device 10A is provided in connection with the second boundary layer control device 10B. and the arrangement of the first boundary layer control device 10A.
More specifically, as shown in FIG. 6, the suction duct 14 of the first boundary layer control device 10A;
The suction duct 14 of the second boundary layer control device 10B and the suction duct 14 of the second boundary layer control device 10B are configured by a common single recess provided on the floor surface, and the suction duct of the second boundary layer control device 10B is partitioned into a plurality of regions 16 by a partition plate 22. Similarly, the suction duct 14 of the first boundary layer control device 10A and the suction duct 14 of the second boundary layer control device 10B are partitioned by a partition plate.
Regarding the arrangement of the first boundary layer control device 10A, the boundary layer suction surface 12 includes a suction surface portion 12A formed between the pair of front wheels FW, a suction surface portion 12B formed between the front wheel FW and the rear wheel RW, and A suction surface portion 12C formed between a pair of rear wheels RW, a region 12D between the front end of the vehicle V and the front wheels FW, and a region 12E between the rear end of the vehicle V and the rear wheels RW are divided into rectangular shapes. good too.
A region 12D from the front end of the vehicle V to the front wheels FW is dominant for the flow downstream from the front wheels FW, while a region 12E from the rear end of the vehicle V to the rear wheels RW is the flow at the rear rear of the vehicle V. It is important to reproduce the rise phenomenon.
More specifically, each of the suction surface portions 12A and 12C extends in the front-to-rear direction of the vehicle.
In the width direction of the vehicle, the width of the opening for the dynamo roller is subtracted from the width of the vehicle. In the width direction of the vehicle, the length corresponding to the vehicle width may be sufficient.
By adjusting the front-rear position of the partition plate 22, the suction duct 14 of the first boundary layer control device 10A may be communicated with the area of the suction duct 14 of the first boundary layer control device 10B at the frontmost portion of the vehicle.
As described above, compared to the case where the first boundary layer control device 10A and the first boundary layer control device 10B are separate and independent, they can be flexibly adjusted according to the test conditions.

In order to confirm the boundary layer suction effect of the boundary layer control device, the applicant conducted the following numerical simulation for flow analysis.
A three-dimensional model for numerical simulation by a computer is shown in FIG.
Flow analysis software is commercially available Fluent (version 19.2).
As shown in Figures 8 and 13, the vehicle, front and rear wheels, and intake duct are modeled on the floor. (12F and 12G), and the space (12A) extending between the pair of front wheels and between the pair of rear wheels, and each wheel and boundary layer suction covering the front of the pair of front wheels and the rear of the pair of rear wheels. Since it is installed in the space between the edge of the surface and is axially symmetrical with respect to the center line extending in the longitudinal direction of the vehicle, only one side is modeled with respect to the center line extending in the longitudinal direction of the vehicle.
Based on the assumption that the airflow flows in the longitudinal direction toward the vehicle placed on the floor, it simulates the intake of air from the intake duct.
Side views of the static pressure distribution around the vehicle are shown in FIGS. 9 and 10 as simulation results.

As shown in FIG. 9, when the suction duct is provided below the floor surface facing the vehicle bottom surface from the front part to the rear part of the vehicle, in the space between the vehicle bottom surface and the floor surface, There is a portion of the boundary layer suction surface about the middle of the direction where the static pressure is lower than the rest of the space.
Due to the existence of such low static pressure areas, the difference between the static pressure in the space between the vehicle underside and the floor and the corresponding static pressure in the intake duct below the floor varies depending on the position in the longitudinal direction of the vehicle. ,different. As a result, as shown in FIG. 11, the wind velocity unevenness of the intake airflow on the boundary layer intake surface occurs, and for this reason, the airflow in the space between the vehicle bottom surface and the floor surface has a different wind velocity distribution and/or flow from that in actual running. direction is triggered. Under the conditions where such wind speed distribution and/or flow direction occurs, it is difficult to conduct precise tests simulating running of a stationary vehicle, even if the boundary layer is sucked in near the floor surface.

On the other hand, as shown in FIG. 10, at 12A, a suction duct is provided below the floor surface facing the vehicle bottom surface from the front to the rear of the vehicle, and the suction duct is divided in the longitudinal direction of the vehicle (5 section), including 12E and 12F, and setting the suction amount, and providing a resistor with a given resistance coefficient on the boundary layer suction surface corresponding to each section, the space between the vehicle undersurface and the floor surface The internal static pressure is clearly shown to be higher than the static pressure inside the duct in each compartment uniformly in the longitudinal direction of the vehicle over the vicinity of the boundary layer suction surface. , clearly shows that the low static pressure portion is eliminated.
Therefore, as shown in FIG. 12, the airflow in the space between the underside of the vehicle and the floor is prevented from having a different wind speed distribution and/or flow direction from the actual running, and the boundary layer suction near the floor is suppressed. By doing so, it becomes possible to conduct a precise test simulating a running vehicle.

According to the above simulation results, depending on the longitudinal length of the vehicle and/or the wind speed of the jet stream, the method of partitioning the intake duct in the longitudinal direction of the vehicle (number of sections) and/or the boundary layer suction corresponding to each section By adjusting the resistance coefficient of the resistor provided on the surface, when the boundary layer near the floor is sucked in, the difference between the underside of the vehicle and the floor caused by the uneven wind speed and/or the direction of the sucked air flow on the boundary layer suction surface. It is shown that it is possible to suppress the occurrence of wind speed distribution and/or flow direction different from actual running in the airflow in the space between.

Although the embodiments of the present invention have been described in detail above, those skilled in the art can make various modifications and changes without departing from the scope of the present invention.
For example, in the present embodiment, the dynamo is arranged below the floor surface for each wheel. In this case, by rotating the dynamo with the dynamo roller, the wheel does not rotate, but the dynamo is directly connected to the rotation axis of the tire. It will be placed in the area where each wheel is removed.
For example, in this embodiment, in the boundary layer control device, in order to control the suction amount of the boundary layer in each partitioned region of the suction duct, the resistor provided on the boundary layer suction surface and the damper 27 provided on the suction pipe , by adjusting the number of rotations of the fan used for suction or the damper 27 in the fan. To the extent that each region may use a different adjustment method, for example, a resistor on the boundary layer suction surface in one region and a damper 27 in another region on the suction pipe, etc., and in the same region, the boundary layer A plurality of adjustment methods, such as a resistor provided on the suction surface and the number of rotations of the blower, may be used.

For example, in the present embodiment, the boundary layer control device includes a second boundary layer control device 10B provided immediately downstream of the wind tunnel outlet 106 and a first boundary layer control device 10A provided below the vehicle arranged in the measurement unit. are driven at the same time, but without being limited to this, as long as the boundary layer can be properly sucked in so as not to interfere with the main stream, for example, only the first boundary layer control device 10A can be driven. , the second boundary layer control device 10B is stopped, the first boundary layer control device 10A is stopped and only the second boundary layer control device 10B is driven, or each region in the first boundary layer control device 10A It may be one that drives only the middle or rear portion of the vehicle. For example, when a wind tunnel test equipment is used to simulate a snowstorm against a vehicle and a blowing test is performed, if the boundary layer is sucked into the suction duct of the boundary layer control device through the boundary layer suction surface, The second boundary layer provided immediately downstream of the wind tunnel outlet 106 is also used because the snowstorm may adhere to the boundary layer suction surface and/or the suction pipe and cause the surface or pipe to close itself. By driving only the control device 10B and stopping the first boundary layer control device 10A provided below the vehicle arranged in the measurement section, or by stopping only the region on the rear side of the vehicle in the first boundary layer control device 10A, It is effective in preventing such a situation.

For example, in the present embodiment, when the boundary layer is appropriately sucked in by the boundary layer control device so as not to interfere with the main flow, in the wind tunnel test device, under a predetermined jot airflow speed based on the set simulated running speed, Although the thickness of the boundary layer that actually occurs is measured and the boundary layer suction amount is adjusted by the boundary layer control device based on the measurement results, the present invention is not limited to this and does not interfere with the mainstream flow. As long as it is possible to absorb the boundary layer appropriately, a theoretical formula of laminar flow on a flat plate or a numerical simulation analysis using a flow model may be used instead of actual measurement.

For example, in the present embodiment, when simulating the running of a vehicle in a wind tunnel test apparatus, the jet stream speed to be generated in the wind tunnel is set based on the set running simulated speed, and according to the set jet stream speed, Although the boundary layer control device determines the amount of boundary layer suction, the present invention is not limited to this. In the case of , as long as the resistor provided on the boundary layer suction surface, the damper 27 provided on the suction pipe, the rotation speed of the blower used for suction, or the boundary layer suction amount adjustment method for the damper 27 in the blower is used, the simulated running speed and The boundary layer suction amount may be stored in a database.

For example, in the present embodiment, the entrained airflow suppressing means 21 applied to the upstream edge and the downstream edge of the opening 36 corresponding to one wheel is the same, but is not limited to this. There may be a brush on the side, a brush on the downstream side, an entrained air flow blocking member on the upstream side, and a brush on the downstream side. A plurality of restraining means may be installed at the downstream edge of one wheel, for example, a brush and an ejector may be used together.
For example, in the first embodiment, for the dynamo roller 38 applied to each wheel, the installation of the entraining airflow suppressing means 21 at the upstream edge and the downstream edge of the opening 36 is common to the entire wheel. However, without limitation, some wheels may be located at the upstream and downstream edges of the opening 36, some wheels may be located at the upstream edge of the opening 36 only, and some wheels may be located at the downstream edge of the opening 36 only.

For example, in this embodiment, after setting the entrained airflow suppressing means 21 that suppresses the space between the vehicle V lower surface LS and the floor surface FL, using the vehicle V to simulate running,
Performance tests, environmental tests, durability tests, etc. have been explained, but when simulating running, the number of revolutions of the dynamo roller 38 and the speed of the jet stream MF in the wind tunnel T fluctuate according to the simulated running speed. For example, the position or size of the flat plate in the first embodiment may be adjusted according to the number of rotations of the dynamo roller 38 to adjust the degree of closing the gap.

1 is an overall schematic diagram of a wind tunnel test apparatus according to a first embodiment of the present invention; FIG. It is a top view of the measurement part of the wind tunnel test device concerning a 1st embodiment of the present invention. FIG. 3 is a detailed partial side view of the measurement section of the wind tunnel test apparatus according to the first embodiment of the present invention; FIG. 3 is a detailed partial side view of the boundary layer control device of the measurement section of the wind tunnel test apparatus according to the first embodiment of the present invention; FIG. 4 is a partial detailed side view of the boundary layer suction surface of the measurement section of the wind tunnel test apparatus according to the first embodiment of the present invention; FIG. 3 is a plan view, similar to FIG. 2, showing a boundary layer control device of a measurement section of a wind tunnel test apparatus according to a second embodiment of the present invention; FIG. 2 is a schematic explanatory diagram showing airflow on the bottom surface and floor surface of a vehicle and/or the rear portion of the vehicle, which are arranged in the measurement section of the wind tunnel test apparatus; FIG. 2 is a three-dimensional model diagram for numerical simulation of static pressure distribution around a vehicle in the boundary layer control device of the measurement section of the wind tunnel test apparatus according to the first embodiment of the present invention; FIG. 5 is a side view showing a simulation result of static pressure distribution around a vehicle when a boundary layer intake duct is provided in the boundary layer control device of the measurement section of the wind tunnel test apparatus according to the first embodiment of the present invention; In the boundary layer control device of the measurement section of the wind tunnel test apparatus according to the first embodiment of the present invention, the boundary layer suction duct is divided into a plurality of regions, and the boundary layer suction surface of each region is provided with a resistor. FIG. 5 is a side view showing a simulation result of static pressure distribution; FIG. 10 is a side view showing the wind velocity distribution in FIG. 9; FIG. 11 is a side view showing the wind velocity distribution in FIG. 10; FIG. 9 is a plan view showing the arrangement of boundary layer suction surfaces in the three-dimensional model diagram of FIG. 8 ;

V Vehicle T Wind tunnel
WH Wheel RW Rear wheel FW Front wheel
W width direction
B1, B2 Entrained air current
C Gap
LS underside
FL Floor surface MF Jet stream
SW Vortex 10A First boundary layer control device 10B Second boundary layer control device 12 Boundary layer suction surface 14 Suction duct 16 Multiple regions 18 Suction means 20 Suction amount adjustment means 21 Entrained airflow suppression plate 22 Partition plate 24 Resistor 26 Suction pipe 27 Damper 29 Blower 30 Inverter 32 Static pressure difference adjusting means 34 Driving simulation device 36 Opening 38 Dynamo roller 23 Uppermost part 24 Upstream edge 28 Downstream edge 35 Centering pipe 100 Wind tunnel test device 101 Fan 102 Rectification tunnel 103 Air duct 104 Contraction tunnel 105 corner vane 106 outlet 107 inlet 108 inlet 109 measurement chamber

Claims (24)

A boundary placed above the vehicle so that it can absorb the boundary layer of the jet stream generated in the space between the underside of the vehicle and the floor when the jet stream generated in the wind tunnel is blown onto the vehicle. A layer suction surface is provided on the floor surface, and a suction duct facing the boundary layer suction surface is provided below the floor surface. a suction amount adjusting means for adjusting the suction amount of the boundary layer to be sucked, and the suction amount adjusting means adjusts when the jet stream flows in the longitudinal direction of the vehicle in the space between the vehicle bottom surface and the floor surface. A static pressure distribution in the longitudinal direction of the vehicle in the space between the underside of the vehicle and the floor caused by the boundary layer being sucked in by the suction means can be adjusted based on the suction amount obtained. A boundary layer control device comprising pressure distribution adjusting means. The static pressure distribution adjusting means measures a first static pressure in the space between the vehicle bottom surface and the floor surface when the jet stream flows in the space between the vehicle bottom surface and the floor surface in the longitudinal direction of the vehicle. 1 static pressure measuring means, a second static pressure measuring means for measuring a second static pressure in the suction duct below the floor surface, and a static pressure difference capable of adjusting the static pressure difference between the first static pressure and the second static pressure. 2. The boundary layer control device of claim 1, comprising adjusting means. 3. The boundary layer according to claim 2, wherein said static pressure difference adjusting means has means for adjusting the static pressure in said suction duct below the floor surface with respect to the static pressure in the space between the vehicle undersurface and the floor surface. Control device. 3. The boundary layer according to claim 2, wherein said static pressure difference adjusting means has means for adjusting the static pressure in the space between the vehicle undersurface and the floor with respect to the static pressure in the suction duct below the floor. Control device. The static pressure difference adjusting means is a partition plate that extends across the width direction of the boundary layer suction surface to partition the suction duct into a plurality of regions. and the suction amount adjustment means adjusts the suction amount of the boundary layer in each area according to the area of the divided boundary layer suction surface determined according to the position of the partition plate in the longitudinal direction of the vehicle. 3. The boundary layer control device of claim 2, wherein: 6. The boundary layer control device according to any one of claims 2 to 5, wherein said static pressure difference adjusting means has a resistor provided on said boundary layer suction surface and forming a resistance to a suction jet stream. 7. The boundary according to claim 6, wherein said resistor is a porous body, and resistors with different resistance coefficients are laminated to reduce suction air velocity distribution unevenness and/or flow direction unevenness on said boundary layer suction surface. layer controller. 2. The boundary layer control device according to claim 1, wherein said suction duct has a suction pipe communicatively connected to said suction means, and said suction pipe is provided with a damper. 2. The boundary layer control device according to claim 1, further comprising stagnation pressure reducing means for reducing stagnation pressure of the jet stream drawn into said suction duct. A driving simulator is placed on the floor below each wheel, and the driving simulator includes an opening provided in the floor and a cylindrical dynamo roller rotatably provided in a non-contact manner with respect to the opening. and a rotation driving means for rotating the dynamo roller about the central axis of the cylinder, the dynamo roller being arranged so that the central axis of the cylinder is positioned below the floor surface, and By rotating the dynamo rollers with the wheels of the vehicle placed on the outer peripheral surface facing the opening, the running of the vehicle is simulated. , a boundary layer control device according to claim 1, disposed in a region excluding said opening. The boundary layer control device is provided so that the boundary layer suction surface is positioned at a predetermined position behind the opening of the dynamo roller on a floor surface facing the bottom surface of the vehicle, and the boundary layer of the boundary layer control device The suction means fills the gap between the dynamo roller and the opening from the dynamo installation room side by entrainment airflow generated by the rotation of the dynamo roller and/or static pressure difference between the dynamo installation room and the bottom surface of the vehicle and the floor surface. 11. The boundary layer control device according to claim 10, which also serves as entrainment airflow suppressing means for suppressing entrainment airflow generated by air flowing in through the opening from reaching the space between the lower surface of the vehicle and the floor surface through the opening. A second boundary layer control device is further provided immediately after the outlet of the wind tunnel, the second boundary layer control device having stagnation pressure reducing means for reducing stagnation pressure of the jet stream sucked into the suction duct, 2. The boundary layer control device according to claim 1, wherein, before the jet stream is blown out to the vehicle, obstruction of the jet stream flowing between the vehicle bottom surface and the floor surface is reduced. When the boundary layer control device according to claim 1 is used to blow out a jet stream generated in a wind tunnel toward a stationary vehicle placed in a measurement room outside the wind tunnel to simulate running, the vehicle is not placed. , measuring the thickness of the boundary layer generated in the vehicle installation area at the portion of the boundary layer suction surface corresponding to each region while changing the velocity of the jet stream; in the step of adjusting the suction amount of the boundary layer, and in a state where the suction amount of the boundary layer is adjusted in each region, the jet stream generated in the wind tunnel is directed toward a stationary vehicle placed in a measurement room outside the wind tunnel. A boundary layer control method characterized by performing various tests on a vehicle. Further, measuring the static pressure distribution between the vehicle bottom surface and the floor surface at each position in the longitudinal direction of the vehicle and the static pressure in the suction duct, and/or adjusting the suction air volume according to the wind speed of the jet stream. adjusting the resistance coefficient of each of the resistors while adjusting, thereby making the static pressure in the suction duct lower than the static pressure between the vehicle underside and the floor. The boundary layer control method according to . 14. The boundary layer control method according to claim 13, wherein the boundary layer suction surface on the vehicle front side is set to have a larger resistance coefficient than the boundary layer suction surface on the vehicle rear side and/or the vehicle center portion. 14. The boundary layer control method according to claim 13, wherein the boundary layer suction surface on the vehicle rear side is set to have a smaller suction amount than the boundary layer suction surface on the vehicle front side and/or the vehicle center portion. When the boundary layer control device according to claim 1 is provided and the jet stream generated in the wind tunnel is blown out through the outlet toward the vehicle arranged in the measurement room outside the wind tunnel, the floor side of the jet stream Wind tunnel test equipment that draws in the generated boundary layer almost vertically below the floor. 18. The wind tunnel testing apparatus of claim 17, wherein the wind tunnel is of a circulating or windsock type. The boundary layer control device may be positioned between a front wheel and a rear wheel and/or between a pair of front wheels, and/or between each front wheel and the edge of the boundary layer suction surface, and/or between a pair of rear wheels. , and/or between each rear wheel and the edge of the boundary layer suction surface. 20. A boundary layer control device according to claim 19, wherein the boundary layer control device is further arranged in a region between the front end of the vehicle and the front wheels and/or in the region between the rear end of the vehicle and the rear wheels. 6. The boundary layer control device according to claim 5, wherein the partition plate is adjustable in position in the longitudinal direction of the vehicle. By blowing a jet stream generated in a wind tunnel toward the vehicle, the boundary layer generated in the space between the bottom surface of the specific vehicle during running simulation and the floor surface is sucked in a predetermined amount using the floor surface as the boundary layer suction surface. measuring the longitudinal static pressure distribution in the space between the bottom surface and the floor of the specific vehicle during running simulation; and measuring the measured longitudinal static pressure distribution during actual running. The boundary layer suction surface is divided in the front-rear direction so as to approximate the actual longitudinal static pressure distribution in the space between the underside of the vehicle and the running surface, and the boundary layer suction surface is divided for each boundary layer suction surface. coarsely adjusting the longitudinal static pressure distribution by adjusting the predetermined amount of suction according to the area of the surface, whereby the pressure distribution between the bottom surface and the floor surface of the specific vehicle during running simulation is provided. A method of simulating vehicle running, characterized by approximating the wind velocity and/or flow direction of a jet stream in space to those of actual running. Furthermore, for each divided boundary layer suction surface, the vertical static pressure difference with the boundary layer suction surface as a boundary is adjusted by selecting the coefficient of resistance when passing through the divided boundary layer suction surface against the boundary layer suction air flow. 23. The vehicle travel simulation method according to claim 22 , further comprising the step of finely adjusting the longitudinal static pressure distribution by: The vehicle travel simulation method according to claim 22 or 23, wherein the step of sucking the boundary layer includes the step of calculating a boundary layer thickness according to a jet stream velocity.

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