JP2000266635A - Boundary layer turbulence-generating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make generable a wind that is similar to natural wind by setting the shape of a spire to a sawtooth shape or that with a number of holes to extend the length of air flow peeling. SOLUTION: The spire 2 is arranged in a wind tunnel 1, and, for example, a number of triangular sawtooth-shaped or triangular through holes are provided at air flow control plates 12a and 12b being mounted onto both the sides of the spire 2. In the control plates 12a and 12b, the upper part is set to multiples points 12ab and 12bb and the spire 2 is pivoted in a suspension shape so that a lower part can be freely rock up and down, and the lower part is rocked up and down in opposite phase by a specific amount by a rocking mechanism, thus extending the length for causing air flow that flows in the wind tunnel 1 to become longer and giving much turbulence by the air flow.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a boundary layer turbulence generator for generating a wind having a turbulent flow characteristic similar to the actual one in a three-dimensional wind tunnel experiment of a bridge or the like.

[0002]

2. Description of the Related Art In a three-dimensional wind tunnel experiment, as shown in FIG. 7, a spear 2 for changing a ventilation area in a height direction of a wind tunnel 1 and a roughness for generating and developing a boundary layer from a floor 1a of the wind tunnel 1. By combining the blocks 3, the wind speed distribution in the vertical direction and the turbulence intensity are made the same as the actual flow. In addition, 4 in FIG. 7 shows a model installed in the measuring unit 1b.

[0003]

In such a conventional three-dimensional wind tunnel experimental apparatus, even if the turbulence strengths match, the scale of the turbulence is small. Therefore, as shown in FIG. A power spectrum (shown by a broken line in FIG. 8) similar to that shown by a solid line in FIG. 8 could not be obtained.

[0004] In other words, in a conventional three-dimensional wind tunnel experiment,
Since you are experimenting with winds in the spectrum where the high frequency range is high, accurate experiments can be obtained in experiments where two or more structures exist upstream and downstream and interfere with each other. The possibility of not being able to do it increases. In particular, this is a problem when a vibration phenomenon of a structure is targeted.

Further, since the space in the wind tunnel is limited, the entire height region of the wind tunnel cannot be made into a natural wind state, and the upper part of the wind tunnel is not disturbed like a natural wind. Therefore, in the case of a tower-like structure such as a chimney,
The wind acting on the upper part of the structure was not in the state of natural wind, but a flow field different from that of the actual machine was to act.

The present invention has been made in view of the above-mentioned problems in the conventional three-dimensional wind tunnel experiment, and is capable of generating a wind similar to a natural wind. It is an object of the present invention to provide a boundary layer turbulence generator which is similar to the above.

[0007]

In order to achieve the above-mentioned object, a first boundary layer turbulence generator according to the present invention is arranged such that the shape of a spear is changed by using a saw blade in order to increase the length of air flow separation. It has a shape or a shape provided with a number of holes. And by making the spyer the shape described above,
More turbulence can be given to the flow.

In the second boundary layer turbulence generator according to the present invention, ventilation control plates are attached to both sides of the speyer, and these ventilation control plates have a saw blade shape or a shape provided with a large number of holes. At the same time, these ventilation control plates are pivotally supported on the spear so as to be freely rotatable about a vertical axis, and can be configured to be rotatable by a predetermined angle by a rotating mechanism,
Alternatively, the spur is pivotally supported so that the lower part can freely swing up and down with the upper part as a fulcrum, and the swing mechanism can vertically swing a predetermined amount. By doing so, in addition to the operation of the first boundary layer turbulence generator according to the present invention, the ventilation area changes due to the rotation or swing of the ventilation control plate. Variations in the frequency domain can be provided.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first boundary layer turbulence generator according to the present invention is a boundary layer turbulence generator in which a spyer and a roughness block are arranged in a wind tunnel, and has a longer airflow separation length. Therefore, the shape of the spear is made a saw blade shape or a shape provided with a large number of holes.

[0010] In the first boundary layer turbulence generator according to the present invention, the spear has a saw blade shape or a shape provided with a large number of holes to increase the air flow separation length. Can give more turbulence.

A second boundary layer turbulence generator according to the present invention is a boundary layer turbulence generator combining a spear and a roughness block arranged in a wind tunnel, wherein a ventilation control plate is attached to both sides of the spear, In order to increase the peeling length, the shape of the ventilation control plate is made a saw blade shape or a shape provided with a number of holes, and these ventilation control plates are rotatable about a vertical axis as a rotation center. The spear is pivoted to a predetermined angle by a pivot mechanism, or the ventilation control plate is pivoted to the spear so that the upper part can be pivoted up and down with the upper part as a fulcrum. It is configured to be able to swing up and down a predetermined amount by a mechanism.

The second boundary layer turbulence generator according to the present invention has the same functions as the first boundary layer turbulence generator according to the present invention described above. The airflow area can be changed by changing the airflow, so that the flow can be varied in a low frequency region.

In the above-described second boundary layer turbulence generator according to the present invention, an opening for bypass introduction is provided on the upstream side of the spider, and an opening for bypass discharge is provided on the downstream side of the measuring section. And, when the bypass introduction opening is provided with an opening area adjusting mechanism, the opening area of the bypass introduction opening is reduced even if the ventilation area changes due to rotation or swing of the ventilation control plate. The adjustment keeps the air volume of the blower unit constant and eliminates pressure fluctuations in the air path.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG.
A description will be given based on the embodiment shown in FIG. FIG. 1 is a longitudinal sectional view showing an embodiment of a boundary layer turbulence generator of the present invention, FIG. 2 is a front view showing an embodiment of a spider, and FIG. FIG. 4B is a front view showing a spider that pivotally supports the ventilation control plate so as to be freely movable, FIG. 4B is an explanatory view of a vertical swing direction of the ventilation control plate, and FIG. FIG. 5B is a front view showing a spyer pivotally supporting the ventilation control plate, FIG. 5B is an explanatory view of a rotation direction of the ventilation control plate, FIG. 5 is a diagram illustrating the principle of a drive system of the ventilation control plate, and FIG. It is explanatory drawing of rotation or rocking | fluctuation control of a board.

In the drawings, reference numeral 11 denotes a spyer arranged in the wind tunnel 1, which has a rectangular saw blade shape as shown in FIG. 2 (a) or a triangular saw blade shape as shown in FIG. 2 (b). Alternatively, as shown in FIG. 2C, a large number of circular through holes 11a are provided.

By forming the spear 11 in such a shape, the length of the airflow flowing in the wind tunnel 1 at which separation occurs becomes longer, and more turbulence can be given to the airflow. This is the first boundary layer turbulence generator according to the present invention.

Numerals 12a and 12b denote ventilation control plates attached to both sides of the spear 2;
The spurs 2a and 12b also have a triangular saw blade shape as shown in FIG. 3A, for example, as shown in FIG. 3A, or a triangular saw blade shape as shown in FIG. , A large number of through holes 12aa and 12ba are provided.

As in the case of the spear 11, the control plate 1
By forming 2a and 12b in such a shape,
The length of the separation of the airflow flowing in the wind tunnel 1 is increased, and more turbulence can be given to the airflow.

A ventilation control plate 12 is provided on both sides of the spear 2.
3A and FIG. 3B, the ventilation control plates 12a and 12b are provided with a fulcrum 12a at the upper part.
As b and 12bb, the lower part is swingably supported on the spear 2 so that the lower part can freely swing up and down, and is configured to swing up and down in a predetermined amount and in opposite phase by a swing mechanism.

FIG. 4 shows the ventilation control plate 1.
Numerals 2a and 12b are configured to pivotally support the spear 2 so as to be rotatable around the vertical axes 12ac and 12bc, and to be rotated at a predetermined angle and opposite phase by a rotation mechanism.

By vertically swinging or rotating these ventilation control plates 12a and 12b in opposite phases, it is possible to change the ventilation area in the wind tunnel 1 and change the airflow in a low frequency region. it can. This is the second boundary layer turbulence generator according to the present invention. These ventilation control plates 12a, 12
The position control of b calculates the spectrum of the fluctuating wind from the measurement result of the fluctuating wind, for example, as shown in FIG.
By comparing this with the target spectrum,
This is performed by obtaining the positions of the ventilation control plates 12a and 12b and repeating the operation of driving the swinging mechanism and the rotating mechanism so as to be at the positions.

The vertical swinging mechanism and the rotating mechanism for vertically swinging and rotating the ventilation control plates 12a and 12b in opposite phases are not particularly limited in structure. The one having the principle configuration as shown in FIG.

That is, in the drive system shown in FIG. 5, the link at the opposite position pivotally supports the middle of one link 13a of the parallel link mechanism 13 having the same length, and pivots at both ends of the link 13a. Linked links 13b, 13c
For example, at the intermediate position, the respective ventilation control plates 12a, 1
Attach rods 14a and 14b pivotally connected to 2b,
One of the links 13b and 13c is pushed and pulled by an actuator 15. According to such a configuration, the ventilation control plates 12a and 12b attached to both sides of the speyer 2 can be vertically rocked or rotated in opposite phases. Reference numeral 16 in FIG. 5 denotes a control device for the actuator 15, which is connected to an adjustment mechanism for a bypass introduction opening 17 described later.

In the second boundary layer turbulence generator according to the present invention, the ventilation control plates 12a and 12b are
If the ventilation area is changed by swinging up and down or rotating in the opposite phase, the whole air in the wind tunnel 1 is accelerated or decelerated, and the pressure in the wind path of the wind tunnel 1 is increased. And the load on the blower also changes. Such changes will adversely affect wind tunnel equipment.

In order to eliminate this adverse effect, as shown in FIG. 1, a bypass introduction opening 17 is provided upstream of the spear 2 having the ventilation control plates 12a, 12b attached to both sides, and a downstream of the measuring unit 1b. On the side, a bypass discharge opening 18 connected to the bypass introduction opening 17 is provided, and the bypass introduction opening 17 is provided with, for example, a damper 19 and an actuator 20 for adjusting the damper 19 to bypass the bypass. The opening area of the introduction opening 17 may be adjusted.

That is, when the ventilation area becomes large due to the vertical swing or rotation of the ventilation control plates 12a and 12b, the actuator 20 is operated and the damper 19 is actuated.
And the opening 17 for bypass introduction is increased
To reduce the opening area. Conversely, when the ventilation area is reduced, the actuator 20 is operated to open the damper 19, and the opening area of the bypass introduction opening 17 is increased by the reduced amount.

In this manner, the bypass introduction opening 1
The airflow introduced from 7 is guided to the bypass discharge opening 18 and returned to the wind tunnel 1 from the bypass discharge opening 18. By doing so, the air volume of the blower unit is kept constant, pressure fluctuation in the air path is eliminated, and the safety of the wind tunnel equipment is increased.

In this embodiment, rectangular or triangular saw blades are formed on the spear 11 and the ventilation control plates 12a and 12b. However, it goes without saying that the present invention is not limited to this. Also, the spyer 11 and the ventilation control plates 12a, 12b
Needless to say, the through holes 11a, 12aa, and 12ba provided in are not limited to circular or triangular shapes.

[0029]

As described above, according to the boundary layer turbulence generator of the present invention corresponding to the first aspect, the spear is formed into a saw blade shape or a shape provided with a number of holes, and the air flow separation is performed. The longer length gives more turbulence to the flow.

The boundary layer turbulence generator according to the present invention according to claim 2 or 3 has the following advantages in addition to the functions and effects of the above-described boundary layer turbulence generator according to claim 1 of the present invention.
Since the ventilation area is changed by rotating or vertically swinging the ventilation control plate, the flow can be varied in a low frequency range. Therefore, the scale of the turbulence can be increased even in the upper part of the wind tunnel, and an airflow closer to the natural wind can be generated.

In the boundary layer turbulence generator according to the present invention, the opening area of the bypass introduction opening is adjusted even if the ventilation area changes due to the rotation or swing of the ventilation control plate. By doing so, the air volume of the blower unit is kept constant, and pressure fluctuation in the air path is eliminated. Therefore, the safety of the wind tunnel equipment is increased.

As described above, according to the boundary layer turbulence generator of the present invention, a boundary layer turbulence field whose spectrum is similar to the actual wind can be obtained, so that the scale of the turbulence is considered to have an effect. Accurate experiments on multiple structures such as bridges are possible. In addition, since almost the entire area of the wind tunnel is a boundary layer turbulence field, accurate experiments can be performed on large-scale models of tower-like structures.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of a boundary layer turbulence generator of the present invention.

FIGS. 2 (a) to 2 (c) are front views showing an embodiment of a spyer.

FIG. 3A is a front view showing a splier in which a ventilation control plate is pivotally supported so that the lower portion can freely swing up and down with an upper portion as a fulcrum, and FIG. 3B is an explanatory diagram of a vertical swing direction of the ventilation control plate. It is.

FIG. 4 (a) is a front view showing a spyer which pivotally supports a ventilation control plate so as to be freely rotatable about a vertical axis,
(B) is an explanatory view of the rotation direction of the ventilation control plate.

FIG. 5 is a diagram illustrating the principle of a drive system for a ventilation control plate.

FIG. 6 is an explanatory diagram of rotation or swing control of a ventilation control plate.

FIG. 7 is an explanatory view of a conventional three-dimensional wind tunnel experimental apparatus, and FIG.
FIG. 2 is a plan view, FIG. 2B is a longitudinal sectional view, and FIG. 2C is a view in which a roughness block when the spire is viewed from the downstream side is omitted.

FIG. 8 is a diagram illustrating a conventional defect.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Wind tunnel 2 Speyer 3 Roughness block 11 Speyer 11a Through hole 12a Ventilation control plate 12aa Through hole 12ab Support point 12ac Vertical axis 12b Ventilation control plate 12ba Through hole 12bb Support point 12bc Vertical axis 15 Actuator 17 Bypass opening 18 Bypass discharge 20 Actuator

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shuji Shirai 1-89, Minami Kohoku, Suminoe-ku, Osaka-shi, Osaka Prefecture F-term in Hitachi Zosen Corporation 2G023 AA03 AB06 AB12 AC03 AD07

Claims (4)

[Claims] In a boundary layer turbulence generator that combines a spear and a roughness block disposed in a wind tunnel, the spear has a saw blade shape or a large number of holes in order to increase the length of air flow separation. Boundary layer turbulence generator characterized by having a curved shape. 2. In a boundary layer turbulence generator in which a spear and a roughness block are combined in a wind tunnel, ventilation control plates are attached to both sides of the spear, and the ventilation control plate is used to increase the length of airflow separation. Is made into a saw blade shape or a shape provided with a large number of holes, and these ventilation control plates are pivotally supported on a spear so as to be freely rotatable about a vertical axis as a center of rotation. A boundary layer turbulence generator characterized by being rotatable. 3. The ventilation control plate is pivotally supported on a spear so that the lower portion can freely swing up and down with the upper portion serving as a fulcrum, and can be vertically swung by a swing mechanism by a predetermined amount. 3. The boundary layer turbulence generator according to 2. 4. A bypass introduction opening is provided on the upstream side of the speyer, a bypass discharge opening is provided on the downstream side of the measuring section, and an opening area adjusting mechanism is provided on the bypass introduction opening. 4. The boundary layer turbulence generator according to claim 2, wherein the boundary layer turbulence generator is provided.