JP2009145259A - Aerodynamic characteristic measuring method of object for improving aerodynamic characteristic, method of optimizing object shape, object optimized using the same, and shape variable model for aerodynamic characteristic evaluating experiment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an object shape optimizing method or the like performed for providing a desired aerodynamic characteristic to an object by using aerodynamic parameters (dynamic lift, aerodynamic sound or the like) determined experimentally. <P>SOLUTION: In the object shape optimizing method for providing the desired aerodynamic characteristic to the object in fluid, a model that simulates the cross-sectional shape of the object and whose profile is variable is used. First, a constraint condition is set in S1, and an initial profile of the cross-sectional shape of the object under the constraint condition is set and the profile of the model is set so as to correspond to the initial profile in S2. The model is placed in the fluid and physical quantity relevant to an action received from the fluid by the model is measured in S3, and an objective function is calculated using the measured value in S4. Until the objective function becomes minimum or maximum in S5, the profile of the cross-sectional shape of the object is changed by the optimizing method (S6), and the profile of the model is changed so as to correspond to the changed profile (S7). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for optimizing the cross-sectional shape of an object by measuring the aerodynamic characteristics of the object using a model of the object in order to improve the aerodynamic characteristics of the object. In particular, the present invention relates to a method for optimizing the cross-sectional shape of a pantograph boat body so that aerodynamic characteristics are improved.

The pantograph is a part that takes in electric energy from the overhead line to the traveling vehicle, and is a part that is necessary to configure the railway vehicle.
FIG. 9 is a perspective view showing an example of the shape of a pantograph.
The pantograph 70 includes a frame 71 installed on the vehicle, and a frame 72 that is attached to the frame 71 and can be vertically expanded and contracted. A boat body 73 is supported on the upper portion of the frame 72 by a boat support. The boat body 73 is an elongated plate-like member extending in the width direction of the vehicle, and is made of, for example, a corrosion-resistant aluminum alloy. A sliding plate 74 that is in contact with the overhead wire is attached to the upper surface of the hull 73. The sliding plate 74 is also a long and thin plate extending in the width direction of the vehicle, and is made of, for example, a copper-based or iron-based sintered alloy.

  Currently, the maximum speed of the Shinkansen reaches 300 km / h, and higher speeds are being considered. In such a high speed region, the influence of the aerodynamic characteristics of the pantograph on the current collecting performance is very large. In particular, the lift characteristics that affect the contact force with the overhead wire and the aerodynamic sound characteristics that affect the noise are important characteristics that affect the performance of the pantograph. However, these two characteristics have contradictory characteristics that if one characteristic is improved, the other characteristic deteriorates, and it is difficult to improve both characteristics at the same time.

  Of the components of the pantograph, a member that greatly contributes to both lift and aerodynamic sound is the hull. Therefore, the determination of the hull shape is very important at the design stage. In general, the shape of a boat body is experimentally obtained by repeating a wind tunnel experiment or the like, but it requires a lot of cost and time, and is a problem.

  In view of this, the present inventors have proposed a method for numerically obtaining the shape of a hull that achieves both suppression of excessive lift and reduction of aerodynamic sound (see Patent Document 1). This method is for obtaining a boat body shape that has a stable lift characteristic with respect to a change in angle of attack and a shape change caused by sliding plate wear and that has a small aerodynamic sound. Specifically, first, an initial value of the hull shape is given, and a flow field around the hull is calculated by CFD (Computational Fluid Dynamics) to evaluate the aerodynamic performance of the hull. Next, the shape of the hull is corrected so as to improve the aerodynamic performance, and the flow field is calculated again to evaluate the aerodynamic performance. This work is performed until it converges to obtain the final hull shape. In other words, optimization is performed with the hull shape as a design variable and the aerodynamic characteristics of the hull as an objective function.

  In general, hydrodynamic optimization problems with an aerodynamic characteristic as an objective function often have multimodality. Therefore, as a design variable optimization method, a method combining the Downhill Simplex method and the annealing method or an evolutionary algorithm was used. This method is a method devised so that the optimal solution does not fall into a local solution, and a global optimal solution can be expected.

  On the other hand, the aerodynamic characteristics of the hull were defined as objective functions as described below. Solves the two-dimensional unsteady uncompressed Navier-Stokes equation by the MAC method (Maker and Cell method) using the upwind difference, and simultaneously obtains the lift characteristics and aerodynamic sound characteristics by changing the ship lift coefficient obtained over time. We decided to evaluate. Aerodynamic sound is generated by a slight acceleration motion in the air around the object due to the fluctuating aerodynamic force generated in the object, and this is propagated. It can be considered that the aerodynamic sound is small. Therefore, both the aerodynamic characteristic evaluation and the aerodynamic sound measurement evaluation can be performed using the lift waveform.

  However, in this method, a good result can be obtained depending on the constraint condition, but under a certain constraint condition, there may be a large difference between the evaluation result and the experimental result. To improve the accuracy, the amount of calculation increases.

Japanese Patent No. 3909314

  The present invention has been made in view of the above-described problems, and is required by optimizing an object shape using aerodynamic quantities (lift, aerodynamic sound, etc.) obtained experimentally. It is an object of the present invention to provide a method for obtaining an object shape having aerodynamic characteristics and a shape variable model for an aerodynamic characteristic evaluation experiment. Of course, it is also meaningful to measure the aerodynamic characteristics of an object using this model.

  The method for measuring aerodynamic characteristics of an object according to the present invention is a method for measuring a physical quantity related to an action of an object in a fluid from a fluid, and is a model imitating a cross-sectional shape of the object, and a model having a variable profile in the fluid. And measuring a physical quantity related to an action that the model receives from a fluid.

According to the present invention, since the profile (cross-sectional shape) of the model is variable, it is possible to relatively easily measure the fluid physical quantity (lift, drag, aerodynamic sound, etc.) when the profile of the object changes. .
The object profile (cross-sectional shape) indicates a cross-sectional shape along the fluid flow direction when the object is placed in a fluid flowing in a certain direction. Further, variable profile means changing the geometric shape of the object cross section, and includes changing it to similar shapes.

  In the present invention, the model is wound along a plurality of two-dimensionally movable frames that define major points, lines, or planes of the outline of the cross-sectional shape of the object. If the film member for forming the outer shape of the model and means for applying tension to the film member are included, the profile of the model can be easily changed by moving the frame two-dimensionally. Can do. In addition, since a means for applying tension to the membrane member is provided, the tension of the membrane member can be maintained even when the profile is changed to change the circumferential length of the cross section. Furthermore, even if the membrane member receives a fluid force in a wind tunnel experiment or the like, the membrane member can be maintained so as not to bend. Further, by providing the film winding device, it is possible to change the circumference of the film portion.

  The object shape optimization method of the present invention is a method for improving the aerodynamic characteristics of an object in a fluid, using a model imitating the cross-sectional shape of the object, the profile of which is variable, and is constant. Set the initial profile of the cross-sectional shape of the object under constraint conditions, set the profile of the model to correspond to the initial profile, place the model in the fluid, and relate the action that the model receives from the fluid Measure the physical quantity to be calculated, calculate the objective function using the measured value, and change the profile of the cross-sectional shape of the object by the optimization method until the objective function reaches the minimum or maximum, and respond to the changed profile Thus, the profile of the model is changed.

In the said patent document, the physical quantity relevant to the effect | action which the object in the fluid receives from the fluid is calculated | required by performing the simulation of a flow field. With this method, good results can be obtained depending on the constraints, but there are many cases where sufficiently accurate calculation results cannot be obtained with current computer resources. Even when a highly accurate solution can be obtained, a very long calculation time is required. In the present invention, since the objective function is evaluated using the physical quantity obtained by the experiment using the model (such as a wind tunnel experiment), a more practical result can be obtained. Since the model has a variable profile, the profile may be changed each time so as to correspond to the profile obtained by applying the optimization method.
As an optimization method, the method described in the above-mentioned patent document (a method combining the Downhill Simplex method and the annealing method or an evolutionary algorithm) can be applied.

  In the present invention, more practical optimization can be performed by providing a plurality of physical quantities to be measured and giving a function including the plurality of physical quantities as the objective function.

  An object of the present invention is an object placed in a fluid, wherein the cross-sectional shape of the object is determined by the following object shape optimization method; improving aerodynamic characteristics of an object in a fluid In order to optimize the cross-sectional shape, a model imitating the cross-sectional shape of the object having a variable profile is used, and an initial profile of the cross-sectional shape of the object under a certain constraint condition is used. Set the model profile to correspond to the initial profile, place the model in the fluid, measure the physical quantity related to the action the model receives from the fluid, and use the measured value An objective function is calculated, and the profile of the cross-sectional shape of the object is changed by an optimization method until the objective function is minimized or maximized, and the object function is changed to correspond to the changed profile. To change the profile of the mold.

  The wind tunnel experiment model of the present invention is a model used for a wind tunnel experiment, and includes a plurality of two-dimensionally movable frames that define major points, lines or planes of the outline of the cross-sectional shape of the object. A membrane member wound along the plurality of frames to form the outer shape of the model; and means for applying tension to the membrane member.

  In this case, the profile of the model can be easily changed by moving the frame two-dimensionally. In addition, since a means for applying tension to the membrane member is provided, the tension of the membrane member can be maintained even when the profile is changed to change the circumferential length of the cross section. Furthermore, even if the membrane member receives fluid force in the wind tunnel experiment, the membrane member can be maintained so as not to bend. Furthermore, by providing the film winding device, it is possible to change the circumferential length of the film member.

  In the present invention, if the mechanism for changing the overall posture of the model is further provided, the angle of attack of the model can be easily changed.

In this invention, it is preferable that the both ends of the said membrane member have come out of the outer side of the both end plate of a wind tunnel experimental apparatus.
This model has a hollow inside whose outer shape is formed of a membrane member. For this reason, it is preferable that both ends of the membrane member protrude outside the both end plates of the wind tunnel experiment device so that the fluid does not enter the inside from both ends of the membrane member.

  In the present invention, the frame defines a principal point of the outline of the cross-sectional shape of the object, a basic member movable in a plane, and a part of the cross-sectional shape removably attached to the basic member It is possible to design the shape of the corner portion of the profile of the model into various shapes (chamfering, rounding).

  In the present invention, assuming that the object is a pantograph hull, fluctuations in the lift of the hull and aerodynamic sound can be easily measured when the profile of the hull is changed.

  The method for optimizing the cross-sectional shape of a pantograph hull according to the present invention is a method for optimizing a cross-sectional shape for the purpose of improving the aerodynamic characteristics of the pantograph hull, and is a model simulating the cross-sectional shape of the hull. And using a model whose profile is variable, generating an initial profile of the cross-sectional shape of the hull under certain constraints, and setting the profile of the model to correspond to the initial profile, Place the model inside, measure the physical quantity related to the action that the model receives from the fluid, evaluate the objective function using the measured value, and use the optimization method until the evaluated value becomes the minimum or maximum The profile of the hull is changed, and the profile of the model is changed so as to correspond to the changed profile.

According to the present invention, for example, by setting an objective function that minimizes lift fluctuation and aerodynamic sound, it is possible to obtain a cross-sectional shape of a hull that has stable lift characteristics and can reduce aerodynamic sound.
In addition, when the profile of the part of the model corresponding to the sliding plate is changed, the aerodynamic characteristics when the sliding plate is worn can be simulated.

As is clear from the above description, according to the present invention, since aerodynamic quantities (lift, aerodynamic sound, etc.) obtained experimentally using a model are optimized, the error of the objective function is small and more Appropriate optimization can be performed. Further, since the objective function is evaluated based on the experimental results obtained by changing the shape of the model, more rational optimization can be performed as compared with the method of evaluating the objective function based on the CFD.
Accordingly, it is possible to provide a method capable of optimizing the cross-sectional shape of an object, particularly a pantograph boat, with high accuracy.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
First, a wind tunnel experiment model according to an embodiment of the present invention will be described.
FIG. 1 is a side view illustrating the entire structure of a wind tunnel experiment model according to an embodiment of the present invention.
FIG. 2 is a plan view of the model of FIG.
FIG. 3 is a cross-sectional view showing an example of a cross-sectional shape of the model of FIG. 1 when the profile is variable.
4 is a perspective view for explaining a frame moving mechanism of the model of FIG.
5A and 5B are diagrams for explaining a part of the frame moving mechanism in FIG. 4. FIG. 5A is a transverse sectional view, and FIG. 5B is a longitudinal sectional view.
FIG. 6 is an enlarged cross-sectional view of a part of a modification of the model frame of FIG.
In this example, a pantograph boat will be described as an example.

  The model 1 is wound along a plurality (four in this example) of frames 10A, 10B, 10C, and 10D and a plurality of frames 10, as shown in FIGS. Is formed by a membrane member 20 and a means for applying tension to the membrane member 20, and in some cases, a membrane winding device is provided, which is a hollow cylinder as a whole.

  As shown in FIG. 2, the frames 10 are arranged in parallel to each other at a position that is a major corner of the outer shape of the cross section of the boat body in plan view. In FIG. 2, the left-right direction in the figure is the front-rear (width) direction of the hull, and the vehicle travels in the left direction in the figure (the wind flows from the left to the right in the figure). In addition, the vertical direction in the figure is the height (thickness) direction of the boat body. That is, as shown in FIG. 3A, the cross-sectional shape is a trapezoidal quadrangle that protrudes forward in the traveling direction. The frame is made of, for example, a stainless steel round bar or pipe. Each frame 10 is supported by a frame moving mechanism 30 shown in FIG.

The frame moving mechanism will be described with reference to FIGS.
The frame moving mechanism 30 extends around the center of the model 1 in the length direction of the frame 10 and extends radially from the central axis 31 so that both ends of the frames 10A, 10B, 10C, and 10D can move. Arms 32A, 32B, 32C, and 32D to be supported, and motors 33A, 33B, 33C, and 33D that rotate the arms around the central axis 31 are provided. In FIG. 4, only the lower part of the model is shown, but the upper part has the same structure. Hereinafter, the lower structure will be described.

  The arm 32 supports the lower end of one frame 10 and is provided so as to extend radially from the vicinity of the lower end of the central shaft 31. The arm 32 is, for example, a linear guide with a built-in magnet. Sliders 35A, 35B, 35C, and 35D having linear motors are fixed to the lower ends of the frames 10A, 10B, 10C, and 10D, and the slider 35 is supported by the arm 32 so as to be movable. That is, when the slider 35 is moved on the arm 32, the distance from the central axis 31 of the frame 10 changes. The two sliders 35 that support one frame 10 are controlled to move in the same direction and at the same speed.

For example, a stepping motor can be used as the motor 33, and as shown in FIG. 5, the motor 33 includes a stator 33a provided coaxially with the central shaft 31 and a rotor 33b disposed around the stator 33a. The base end of each arm 32 is fixed to the rotor 33b. When the motor 33 is driven and the rotor 33b rotates, the angle of the arm 32 with respect to the central axis 31 changes. The motor 33 to which the two arms 32 supporting one frame 10 are fixed is controlled so that the two arms 32 rotate in the same direction and at the same speed.
Since there are a plurality of frames 10, the motor 33 provided for each frame is arranged side by side in the length direction near both ends of the central shaft 31 as shown in FIGS. 4 and 5B. (Only a part is shown in the figure).

  As described above, each frame 10 is two-dimensionally moved by moving the slider 35 along the linear guide (arm) 32 and rotating the arm 32 about the central axis 31 by the motor 33. Can be moved. The position of each frame 10 is managed on coordinates, and the moving distance of the slider 35 and the rotation angle of the motor 33 are controlled so that each frame 10 can move to an appropriate position. For example, when the profile of the model is set in a state where the sliding plate is worn, as shown in FIG. 3A, the frames 10D and 10C are moved by a predetermined amount in the height direction (Y direction) (wear amount). ) To change the height (thickness) of the model 1 by setting the rotation angle of the arm 32 and the movement distance of the slider 35. Note that the circumferential length of the membrane member 20 changes as the frame 10 moves as described above, and this change is adjusted by a membrane member winding device described later.

  The film member 20 is, for example, a belt-shaped member made of polyethylene (film thickness 0.07 mm) or the like, and is wound so as to surround the entire frame 10. As shown in FIG. 4, both ends of the membrane member 20 are fixed to a membrane winding device arranged on the axis of the central shaft 31 via a membrane fixing device 40. The membrane fixing device 40 is disposed between two adjacent frames 10B and 10C, and includes two members 41a and 41b that sandwich the membrane member 20 from both sides. Even if the frame moves, the membrane fixing device 40 can always move so as to be positioned on a straight line connecting the two adjacent frames 10B and 10C. That is, in the membrane fixing device 40, like the frame moving mechanism, the slider 35E is fixed to both ends, and the slider 35E is supported by the arm 32E so as to be movable. The arm 32E is rotatable around the central axis 31 by a motor 33E arranged coaxially with the central axis.

  Both ends of the membrane member 20 are sandwiched between the two members 41a and 41b of the membrane fixing device 40, and then extend in the direction of the central axis 31 to be wound around the membrane winding device. The winding device can be constituted by, for example, a rotor 43 provided coaxially with the central shaft 31 and fixed at both ends of the membrane member 20 and a motor (not shown) for rotating the rotor 43. . As described above, when each frame 10 moves, the circumference of the membrane member 20 changes. Then, since the membrane member 20 may be pulled or bent, the membrane winding device adjusts the peripheral length so that the membrane member 20 is always stretched between the frames. For example, when the frame 10 moves so as to increase the perimeter, the membrane winding device rotates to feed out the membrane member 20, and conversely, when the frame 10 moves so as to shorten the perimeter, the device becomes a membrane. It rotates so that the member 20 may be wound up. Further, tension is applied so that the membrane member 20 does not bend during the wind tunnel experiment.

  As shown in FIG. 1, both ends of the central shaft 31 are fixed to the support plate 50. Each support plate 50 is fixed to the rotary table 51. By rotating the turntable 51, the angle of attack of the model 1 can be changed as shown in FIG. In addition, a force sensor 52 is attached to each support plate 50, and the force related to the plate 50, that is, the force related to the model 1 can be measured.

In the model of FIG. 1, a rod-shaped frame having a circular cross section is used as the frame. However, as shown in FIG. 5, the subframe 11 for shape reproduction is placed outside the frame 10 (the side around which the membrane member 20 is wound). It is preferable to attach. As the sub-frame 11, a cross-sectional shape having an acute angle as shown in FIG. 6A or a semi-circular shape having a semi-circular shape as shown in FIG. 6B can be used. By providing such a sub-frame 11, it can be designed to give various roundness to the corners of the model profile.
In addition to the above, it is possible to give the model a fine shape that does not need to be changed by using a trapezoidal cross section as the subframe 11 in order to give a chamfered shape to the corner of the model profile.

  In this example, the frame 10 can be moved automatically, but may be moved manually. Or you may use both together.

  The model 1 described above is hollow, but there are many actual objects including the hull. Since the aerodynamic characteristics may be different between the hollow model and the solid model, we compared the aerodynamic characteristics of the hollow model and the solid model by wind tunnel experiments.

FIG. 7 is a graph showing aerodynamic characteristics of the hollow model and the solid model. The vertical axis represents drag coefficient and the horizontal axis represents wind speed.
As shown in the graph, when the wind speed is 10m / s to 40m / s, the drag coefficient of both the hollow model shown by ◇ in the figure and the solid model shown by ■ in the figure is about 1.2. I couldn't see it. In other words, it was confirmed that the hollow model exhibits almost the same aerodynamic characteristics as the solid model.

Next, a cross-sectional shape optimization method performed for the purpose of imparting desirable aerodynamic characteristics to the boat body using this wind tunnel experimental model will be described.
FIG. 8 is a flowchart for explaining a cross-sectional shape optimization method for imparting desirable aerodynamic characteristics to an object according to an embodiment of the present invention.
First, in step S1, a constraint condition is set. The constraint conditions are, for example, the width and minimum thickness of the hull, which are inevitably determined in consideration of the strength of the hull. Next, based on this constraint condition, an initial profile of the model 1 is determined in step S2, and each frame 10 of the model 1 is moved so as to correspond to the profile by the above-described method.

In the following example, optimization for minimizing both ship lift variation and aerodynamic noise reduction will be described.
After that, in step S3, a wind tunnel experiment is performed by changing the profile of the model 1 so as to correspond to a predetermined setting condition to be described later, and the force sensor 52 measures a time change of lift acting on the model 1 under each setting condition. And determine the lift coefficient. When performing the wind tunnel experiment, the model 1 is installed so that both open ends (side edges of the membrane member 20) of the model 1 are outside the end plate E of the wind tunnel experiment apparatus W as shown in FIG. . Since the inside of the model 1 formed by the membrane member 20 is hollow, the model 1 cannot accurately evaluate the aerodynamic force acting on the model when fluid enters the inside from both side edges of the membrane member 20. . Therefore, both ends of the membrane member 20 are positioned outside the both end plates E of the wind tunnel experimental device W so that the fluid does not enter the inside.
In addition to lift, aerodynamic sound, pressure distribution, flow velocity distribution, and the like can also be measured. When aerodynamic sound is measured, a sound collecting device such as a microphone is installed at a predetermined distance from the model to measure the sound.

The setting condition is a condition for obtaining a value necessary for calculation of an objective function described later, and this time is defined as follows similarly to Japanese Patent No. 3909314.
Setting condition 1: sliding plate; not worn, angle of attack; +3 degrees,
Setting condition 2: sliding plate; not worn, angle of attack; -3 degrees
Setting condition 3: sliding plate; worn state (wear amount 6 mm), angle of attack; +3 degrees,
Setting condition 4: sliding plate; worn state (amount of wear 6 mm), angle of attack: −3 degrees.

When setting the model profile in a state where the sliding plate is worn, as shown in FIG. 3A, the arms of the frames 10B and 10C are rotated so that the height of the model is reduced by the wear amount. Slide on the arm. The change in the circumferential length of the membrane member 20 accompanying the movement of the frame 10 is adjusted by the membrane member winding device.
When adjusting the attack angle of the model, as shown in FIG. 3B, the rotary table 51 is rotated by a predetermined angle.

  Next, in step S4, the aerodynamic characteristics (lift fluctuation and aerodynamic sound) are evaluated using the value of the lift coefficient obtained under the above set conditions. The evaluation method is performed using the following objective functions 1 (Equation 1) and 2 (Equation 2), which are the same as those in Patent Document 1. In either case, we aim to minimize the objective function.

  In the above formula, a and b are coefficients, Cl is a lift coefficient, new is a state where the sliding plate is not worn, old is a state where the sliding plate is worn, ave is an average value, rms is an effective value, and α is Indicates the angle of attack (degrees). The lift coefficient obtained in the wind tunnel experiment under the aforementioned setting conditions is substituted into objective function 1 (Equation 1) and objective function 2 (Equation 2).

The objective function 1 represents the difference between the maximum value and the minimum value of the lift coefficient in all cases under the above-described setting conditions.
The objective function 2 is a weighted sum of the difference between the maximum average value and the minimum average value and the maximum effective value among all cases of the above setting conditions. Show.

  In the present embodiment, the optimum shape is obtained by minimizing the objective function related to the change in the angle of attack. Here, aerodynamic sound is considered to be the propagation of subtle acceleration motion generated in the air around the object due to fluctuations in the force received from the object. Therefore, if the frequency space is ignored, an object with small lift fluctuation has low aerodynamic sound. Can be considered. In particular, for “objective function 2”, minimizing the portion multiplied by coefficient “a” in Equation 2 is related to minimizing lift fluctuations, and minimizing the portion multiplied by coefficient “b”. This is related to minimizing noise because the effective value can be considered as the cause of the acceleration motion.

  Next, in step S5, it is determined whether the objective function has converged. If it is determined that it has not converged, the process advances to step S6 to perform optimization calculation. The optimization operation is to determine the value of the variable so that the objective function is minimized (or maximized) among those satisfying the constraint conditions. Here again, the Downhill Simplex method is the same as in the above-mentioned patent document. And a combination of annealing methods can be used. Since this method is described in the aforementioned Japanese Patent No. 3909314, the description thereof is omitted.

  In step S6, a profile to be set next (secondary profile, position coordinates of each frame) is determined based on the value of the objective function. In step S7, each frame 10 is moved so that the profile of the model 1 corresponds to the set secondary profile. Then, proceed to the step, and conduct a wind tunnel experiment in the same way and perform optimization. This is repeated until the objective function converges in steps.

In the method described above, a model having four frames 10 is used. However, the number of frames 10 can be appropriately changed depending on the shape of the object. Further, in order to obtain the final cross-sectional shape of the object, the shape of the corner set by the frame is approximated by a predetermined function.
The model 1 can also be used only for measuring aerodynamic characteristics (lift, aerodynamic sound, etc.).

It is a side view explaining the whole structure of the model for wind tunnel experiment concerning embodiment of this invention. It is a top view of the model of FIG. It is a cross-sectional view which shows an example of the cross-sectional shape at the time of profile change of the model of FIG. It is a perspective view explaining the frame moving mechanism of the model of FIG. 5A and 5B are diagrams for explaining a part of the frame moving mechanism in FIG. 4. FIG. 5A is a cross-sectional view, and FIG. 5B is a vertical cross-sectional view. It is the cross-sectional view which expanded a part of modification of the frame of the model of FIG. It is a graph which shows the aerodynamic characteristic of a hollow model and a solid model. It is a flowchart explaining the cross-sectional shape optimization method for providing the desired aerodynamic characteristic to the object which concerns on embodiment of this invention. It is a perspective view which shows an example of the shape of a pantograph.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Model 10 Frame 20 Membrane member 30 Frame moving mechanism 31 Center shaft 32 Arm 33 Motor 35 Slider 40 Membrane fixing device 41 Member 43 Rotor 50 Support plate 51 Rotary table 52 Force sensor

Claims (11)

In a method of measuring a physical quantity related to an action of an object in a fluid from the fluid,
An aerodynamic characteristic measurement of an object, which is a model imitating a cross-sectional shape of the object, wherein a model having a variable profile is installed in a fluid, and a physical quantity related to an action that the model receives from the fluid is measured. Method. A plurality of two-dimensionally movable frames in which the model defines major points, lines or planes of the outline of the cross-sectional shape of the object;
A membrane member wound along the plurality of frames to form the outer shape of the model;
Means for applying tension to the membrane member;
The method for measuring aerodynamic characteristics of an object according to claim 1. In the method of optimizing the cross-sectional shape for the purpose of improving the aerodynamic characteristics of the object in the fluid,
Using a model imitating the cross-sectional shape of the object, the profile of which is variable,
Set an initial profile of the cross-sectional shape of the object under certain constraints,
Setting the profile of the model to correspond to the initial profile;
Placing the model in a fluid and measuring the physical quantities related to the action the model receives from the fluid;
The objective function is calculated using the measured value,
The object shape optimization is characterized in that the profile of the cross-sectional shape of the object is changed by an optimization method until the objective function becomes minimum or maximum, and the profile of the model is changed to correspond to the changed profile. Method.   4. The object shape optimization method according to claim 3, wherein the objective function includes a plurality of physical quantities to be measured. An object placed in a fluid,
An object characterized in that the cross-sectional shape of the object is determined by the following object shape optimization method;
In the method of optimizing the cross-sectional shape of an object for the purpose of achieving the desired aerodynamic characteristics of the object in the fluid,
Using a model imitating the cross-sectional shape of the object, the profile of which is variable,
Set an initial profile of the cross-sectional shape of the object under certain constraints,
Setting the profile of the model to correspond to the initial profile;
Placing the model in a fluid and measuring the physical quantities related to the action the model receives from the fluid;
The objective function is calculated using the measured value,
Until the objective function becomes the minimum or maximum, the profile of the cross-sectional shape of the object is changed by an optimization method, and the profile of the model is changed to correspond to the changed profile. A model used in wind tunnel experiments,
A plurality of two-dimensionally movable frames defining major points, lines or planes of the outline of the cross-sectional shape of the object;
A membrane member wound along the plurality of frames to form the outer shape of the model;
Means for applying tension to the membrane member;
A wind tunnel experimental model characterized by comprising:   The wind tunnel experiment model according to claim 6, further comprising a mechanism for changing an overall posture of the model.   The wind tunnel experiment model according to claim 6 or 7, characterized in that both ends of the membrane member protrude outside the both end plates of the wind tunnel experiment apparatus. The frame is
A basic member that is movable in a plane and that defines the main points of the outline of the cross-sectional shape of the object;
The wind tunnel experimental model according to claim 6, 7 or 8, further comprising a setting member which is removably attached to the basic member and forms a part of the cross-sectional shape.   The wind tunnel experimental model according to claim 5, wherein the object is a pantograph boat. A cross-sectional shape optimization method for the purpose of improving the aerodynamic characteristics of the pantograph hull,
Using a model simulating the cross-sectional shape of the hull, the profile of which is variable,
Generating an initial profile of the cross-sectional shape of the hull under certain constraints,
Setting the profile of the model to correspond to the initial profile;
Placing the model in a fluid and measuring the physical quantities related to the action the model receives from the fluid;
Evaluate the objective function using the measured value,
A cross section of a pantograph hull, wherein the profile of the hull is changed by an optimization method until the evaluation value becomes minimum or maximum, and the profile of the model is changed to correspond to the changed profile. Shape optimization method.

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