JP2002048672A - Aerodynamic force measuring apparatus and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aerodynamic force measuring apparatus and method which enable measuring of a non-.steady aerodynamic force at a higher accuracy with a load cell of a relatively small capacity in any case where an aerodynamic force is large or is where the level of the aerodynamic force is very small in the measurement of the aerodynamic force working on a model arranged in an air flow space with the load cell. SOLUTION: A model arranged within an air flow space such as air tunnel is mounted on a frame and when the model is vibrated by an exciting means through the frame to measure the aerodynamic force working on the model by an air flow, the model is suspended through an elastic support member from the frame to support the weight of the model. A lower part of the model is linked to the load cell to make the aerodynamic force work mainly on the load cell so that the position of a link part is changed between a drive link mechanism and the frame. This allows the frame and the model to select vertical movement or rotary motion through the exciting means and the drive link mechanism.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an unsteady aerodynamic force in a model disposed in an airflow space through which air flows, such as a wind tunnel test for a bridge, a chimney, a windmill, a building to be damped, and the like. TECHNICAL FIELD The present invention relates to an aerodynamic measuring device and a measuring method for measuring a force.

[0002]

2. Description of the Related Art In a wind tunnel test for a bridge, a chimney, a windmill, a building to be damped, and the like, a model of the bridge, a chimney, a windmill, a building to be damped, and the like disposed in an airflow space of the wind tunnel. Is attached to a frame connected to the vibrating means, and the vibrating means applies vibration to the model via the frame to measure an aerodynamic force acting on the model by an air flow via a load cell. . FIG. 5 is a front configuration diagram showing one example of a conventional technique of an unsteady aerodynamic force measuring device for applying vibration to a model and measuring aerodynamic force acting on the model in such a wind tunnel test.

In FIG. 1, reference numeral 100 denotes a model disposed in an air flow path 101 in a wind tunnel, and 1 denotes a frame formed of a quadrangular frame. Are supported so as to be movable in the vertical direction (the direction of the arrow Y in the figure). 020 is an upper member 1a of the frame 1.
A plurality of load cells attached to the model 100
Is suspended from the load cell 020 via the support cable 05. The lower portion of the model 100 is connected to a lower member 1b of the frame 1 via a spring 4. Further, a side portion of the model 100 is connected to a side member 1c of the frame 1 via a spring 04. 10
Is a motor connected to the frame 1 via a drive link 6, and the excitation force from the motor 10 is applied to the drive link 6.
The vibration is transmitted to the frame 1 via the frame 1 and the desired vibration is applied to the frame 1 and the model 100.

[0004] In a wind tunnel test using such an unsteady aerodynamic force measuring device, the model 1
While transmitting an airflow to the frame 1, the motor 10 transmits, for example, a vertical excitation force indicated by an arrow Y in FIG. 5 to the frame 1 via the drive link 6. As a result, a desired mode of vibration is applied to the frame 100 and the model 100 placed in the air flow path 101. And, the aerodynamic force generated in the model 100 by the vibration,
The measurement is performed by the load cell 020 which suspends the model 100.

Japanese Patent Application Laid-Open No. 51-36985 discloses a technique for measuring the unsteady aerodynamic force generated in a model placed in a wind tunnel by applying vibration to the model. The unsteady aerodynamic force measuring device according to the invention includes a balance mechanism for canceling an inertial force generated in the model due to a forced vibration of the model placed in a wind tunnel, and a model under forced vibration with respect to the balance mechanism. Detecting means connected so as to separately detect only the lift and the moment are provided, so that a small lift and a moment can be measured with high accuracy under a large forced excitation force.

[0006]

However, the conventional unsteady aerodynamic force measuring device as shown in FIG. 5 has the following problems. That is, the model 1
The load cell 020 for detecting the unsteady aerodynamic force generated at 00 needs to have a capacity (withstand load) corresponding to the maximum load generated in the model 100. Load the model 100 with the load cell 0
Since the load cell 020 is suspended from the support 20 via the support cable 05, the load cell 020 measures the aerodynamic force generated in the model 100 and the weight of the model 100 itself (the aerodynamic force is measured by the load cell 020). 100 from value
Deduct the weight).

For this reason, in the prior art, it is necessary to make the load cell 020 of a large capacity (withstand load) by adding the aerodynamic force and the weight of the model 100 itself, and a minute aerodynamic force is measured. In this case, measurement errors are likely to occur, especially when the aerodynamic force oscillates with a small amplitude in a small average aerodynamic force level. There is a problem that. Also, in the invention of Japanese Patent Application Laid-Open No. 51-36985, no consideration is given to the elimination of measurement errors when measuring minute aerodynamic forces.

In view of the above-mentioned problems of the prior art, the present invention measures the air force acting on a model disposed in an airflow space by using a load cell, and the load cell has a relatively small capacity. It is an object of the present invention to provide an aerodynamic force measuring device and a measuring method capable of measuring unsteady aerodynamic force with high accuracy both in a case where the aerodynamic force is large and a case where the level of the aerodynamic force is minute.

[0009]

In order to solve the above-mentioned problems, the present invention relates to a method of connecting a model disposed in an air flow space such as a wind tunnel through which air flows, to a vibration means. An aerodynamic force measuring apparatus which is attached to a frame which has been applied, and which applies vibration to the model via the frame by the vibrating means and measures an aerodynamic force acting on the model by an air flow via a load cell. An air force measuring device, wherein the model is suspended from the frame via an elastic support member, the load cell is installed at a lower portion of the frame, and the lower portion of the model is connected to the load cell. I do.

The invention according to claims 2 and 3 relates to a specific structure of the elastic support member. According to the invention of claim 2, the elastic support member is interposed between the frame and the upper part of the model. It is characterized by being constituted by a set spring. The invention according to claim 3 is characterized in that the elastic support member is constituted by a linear motor attached to an upper portion of the frame and having an output end connected to an upper portion of the model.

The invention according to claim 6 is the first to third aspects of the present invention.
A method using the air force measuring device according to the invention described in claims 4 and 5, wherein a model disposed in an air flow space through which air flows, such as a wind tunnel, is used as a vibration means. Attaching to a connected frame, the vibration means applies vibration to the model through the frame through the frame, and measures an air force acting on the model by an air flow through a load cell. The model is suspended from the frame via an elastic supporting member, the weight of the model is supported by the elastic supporting member, the lower part of the model is connected to the load cell, and the load cell receives the aerodynamic force generated in the model. It is characterized by acting independently.

According to the invention, the model is suspended from the upper part of the frame via the elastic support member, and the load cell is attached to the lower part of the frame and connected to the lower part of the model. The weight of the model will be loaded on the elastic support member suspending the model,
Only the aerodynamic force generated in the model is applied to the load cell, and the load cell can measure only the aerodynamic force generated in the model. Therefore, according to the invention, as described above,
Since the load cell can measure only the aerodynamic force generated in the model, even in the case of minute aerodynamic force, especially when the aerodynamic force oscillates with a small amplitude in a small average aerodynamic force level, the measurement error can be reduced. The aerodynamic force can be measured without generating the following. Further, as described above, since the load cell can measure only the aerodynamic force generated in the model, even if the aerodynamic force is large, the load cell can be measured with a relatively small capacity load cell without causing a measurement error. Can be measured.

According to the third aspect of the present invention, the initial tension is applied to the support rope of the model by the linear motor according to the weight of the model so that the weight of the model is not applied to the load cell. Even when a heavy model is used, the weight of the model can be reliably supported by the linear motor, and the aerodynamic force can be measured with high accuracy without increasing the capacity of the load cell.

According to a fourth aspect of the present invention, in the first aspect, the frame is vertically movable and rotatable about a central axis of the model and is supported by a fixed member, and the frame is driven by the vibration means. It is characterized in that it is configured to move up and down or rotate around the central axis via a link mechanism. According to a fifth aspect of the present invention, in the fourth aspect, the connecting portion between the drive link mechanism and the frame is movable, and the position of the connecting portion is changed, so that the frame and the model are added to the frame and the model. The vertical movement via the vibration means and the drive link mechanism or the rotation about the central axis can be selected.

According to the present invention, by changing the position of the connecting portion between the drive link mechanism and the frame 1, 1
With one aerodynamic measuring device, vertical vibration or torsional vibration around the center of the model can be selectively imparted to the frame and the model from the vibration means via the drive link mechanism, which complicates the device. The vibration function can be expanded without the need.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to an embodiment shown in the drawings. However, unless otherwise specified, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention thereto, but are merely illustrative examples. It's just

FIG. 1 is a front view of a main part of an unsteady aerodynamic force measuring device for a wind tunnel test according to a first embodiment of the present invention. FIG.
1A and 1B show a method of applying vibration in the first embodiment, and FIG. 1A shows a case where vertical vibration is applied, and FIG. 1B shows a case where rotational vibration is applied. FIG. 3 is a view as viewed from the direction of arrows AA in FIG.
FIG. 4 is a main part front view showing the second embodiment.

1 to 3 showing the first embodiment, reference numeral 100 denotes a model, which is disposed in an air passage 101 of a wind tunnel. Reference numeral 1 denotes a frame formed of a quadrangular frame. The frame 1 can be moved vertically (in the direction of the arrow Y in the drawing) on a support column 2 by means to be described later, and
It is supported rotatably around 5. The model 100
Is suspended from the upper member 1 a of the frame 1 via a plurality of springs 4. Reference numeral 20 denotes a plurality of load cells attached to the lower member 1b of the frame 1. The load cells 20 are connected to the lower part of the model 100 by a connecting member 5, and the aerodynamic force generated in the model 100 is transmitted through the connecting member 5. So as to hang on the load cell 20. Further, a side portion of the model 100 is connected to a side member 1c of the frame 1 via a spring 04. A motor 10 is connected to the frame 1 via a crank 7 and a drive link 6 which will be described later.
Is transmitted to the frame 1 via the crank 7 and the drive link 6, and the frame 1 and the model 10
A desired vibration is applied to zero.

FIG. 3 shows details of the support structure for the model 100 and the frame 1. In FIG. 3, reference numeral 101 denotes an air passage in the wind tunnel, 102 denotes a wall of the wind tunnel, and a model supporting device 200 including the frame 1 includes It is provided inside the wind tunnel wall 102. Reference numeral 2 denotes a support as a fixing member, reference numeral 14 denotes a rotating base fixed to the support 2, reference numeral 12 denotes a bearing, and reference numeral 13 denotes a rail mount. One end of the bearing portion 12 is rotatably fitted in a circular hole formed in the rotary mount 14, and the rail mount 13 is fixed to the other end. The rail stand 13
A guide rail 9 extends in the vertical direction on the side opposite to the bearing 12, and the frame 1 is fitted to the guide rail 9 so as to be movable in the vertical direction. Therefore, the frame 1 rotates around the model rotation center 15 (N
Direction), and can be moved in the vertical direction (Y arrow direction) guided by the guide rail 9.

The motor 10 for moving or rotating the frame 1 in the vertical direction is fixed to a lower portion of the column 2. A crank 7 is connected to an output shaft 010 of the motor 10. The drive link 6 having an upper end connected to the frame 1 is connected to the crank 7.
7 are connected. Therefore, the motor 10 and the frame 1 are connected by a known piston-crank mechanism including the crank 7, the crank pin 07, and the drive link 6, and the rotational motion of the motor 10 is converted into the reciprocating motion of the frame 1. It is designed to convert.

In the unsteady aerodynamic force measuring device for wind tunnel test having such a configuration, the model 100 placed in the air flow path 101 is exposed to an air flow at a predetermined flow velocity. On the other hand, the rotational force corresponding to a desired vibration mode output from the motor 10 passes through an output shaft 010 of the motor 10 and is vertically moved by a crank 7, a crank pin 07, and a drive link 6 configured in a piston-crank mechanism. Is transmitted to the frame 1. As a result, the frame 1 and the frame 1,
4 is attached to the model 100 shown in FIG.
Vibrating up and down as indicated by the arrow Y. The air force generated in the model 100 by being vibrated in the airflow as described above is measured by the load cell 20 connected to the lower part of the model via the connecting member 5.

In this embodiment, the model 100
Is suspended from the upper member 1a of the frame 1 via a plurality of springs 4, and the load cell 20 is attached to the lower member 1b of the frame 1 and connected to the lower part of the model 100 by the connecting member 5. The model 10
0 is applied to the spring 4 which suspends the model 100, and the load cell 20
Only the aerodynamic force generated in the above is applied via the connecting member 5,
The load cell 20 can measure only the aerodynamic force generated in the model 100.

Therefore, according to this embodiment, as described above, since the load cell 20 can measure only the aerodynamic force generated in the model 100, in the case of a small aerodynamic force, in particular, the average aerodynamic force having a small aerodynamic force is small. Even in the case of vibrating with a small amplitude in the force level, the aerodynamic force can be measured without causing a measurement error. Further, as described above, since the load cell 20 can measure only the aerodynamic force generated in the model 100, even when the aerodynamic force is large, a relatively small capacity load cell does not cause a measurement error. Can measure aerodynamic force.

FIG. 2 shows a method of applying vibration to the frame 1 and the model 100 in the first embodiment shown in FIGS. In the present invention, a connection portion 21 or 22 between the drive link 6 and the lower member 1b of the frame 1 is provided.
Is configured to be movable. That is, as shown in FIG. 2A, the drive link 6 and the lower member 1b of the frame 1 are formed.
If the connecting portion 21 is arranged at a position where the drive link 6 is vertical, the direction of the exciting force (vibration) transmitted from the motor 10 to the frame 1 via the drive link 6 is
The frame 1 is guided by the guide rail 9 and vibrated in the vertical direction as indicated by the arrow Y in FIG.

As shown in FIG. 2B, a connecting portion 22 between the drive link 6 and the lower member 1b of the frame 1 is formed.
Are disposed at the corners of the frame 1 such that the drive link 6 is inclined with respect to the frame 1, so that the motor 10
The direction of the excitation force (vibration) from the direction is oblique to the frame 1, and therefore, the frame 1 and the model 100 are interposed via the bearing 12 and the rotating base 14 as shown by an arrow N in FIG. It becomes rotatable, and the model 100 can be subjected to torsional mode vibration.

According to this embodiment, the driving link 6
By changing the position of the connecting portion 21 or 22 of the frame 1 and the frame 1, one frame of the frame 1 and the model 100 can be vertically vibrated from the motor 10 via the drive link 6 by one aerodynamic measuring device. Or model center 15
The surrounding torsional vibration can be selectively applied, and the vibration function can be expanded without complicating the device.

In the second embodiment of the present invention shown in FIG. 4, instead of the springs 4 and 04 in the first embodiment,
A plurality of linear motors 3 are mounted on an upper member 1a of the frame 1.
0, and the output end of the linear motor 30 is
1 and connected to the model 100. The guide rail 9 on which the frame support 11 is vertically movably fitted is attached to the support column 2 via a spherical joint 32 so that the frame 1 can rotate around the model rotation center 15. And Incidentally, the spherical joint portion 32 can be provided also in the first embodiment.

According to this embodiment, the linear motor 30 applies an initial tension to the support rope 31 according to the weight of the model 100 so that the weight of the model 100 is not applied to the load cell 20. Thus, even when using a heavy model 100, the linear motor 30 can reliably support the weight of the model 100, and the aerodynamic force can be measured with high accuracy without increasing the capacity of the load cell 20. Become.

[0029]

As described above, according to the present invention, the model is suspended from the upper part of the frame via the elastic support member, and the load cell is attached to the lower part of the frame and connected to the lower part of the model. Therefore, the weight of the model is applied to the elastic support member suspending the model, and the load cell can measure only the aerodynamic force generated in the model. This makes it possible to measure the aerodynamic force without any measurement error, even in the case of small aerodynamic forces, especially when the aerodynamic force oscillates with a small amplitude in a small average aerodynamic force level. . Further, as described above, since the load cell can measure only the aerodynamic force generated in the model, even if the aerodynamic force is large, the load cell can be measured with a relatively small capacity load cell without causing a measurement error. Can be measured.

According to the third aspect of the present invention, the initial tension is applied to the support rope of the model by the linear motor according to the weight of the model, so that the weight of the model is not applied to the load cell. Even when a heavy model is used, the weight of the model can be reliably supported by the linear motor, and the aerodynamic force can be measured with high accuracy without increasing the capacity of the load cell.

Further, according to the fourth and fifth aspects, the position of the connecting portion between the drive link mechanism and the frame 1 is changed so that one aerodynamic force measuring device can be used.
Vertical vibration or torsional vibration around the center of the model can be selectively imparted to the frame and the model from the vibration means via the drive link mechanism, and the vibration function can be expanded without complicating the apparatus.

In short, according to the present invention, the unsteady aerodynamic force can be measured with high accuracy both when the aerodynamic force is large due to the load cell having a relatively small capacity and when the level of the aerodynamic force is very small. Becomes

[Brief description of the drawings]

FIG. 1 is a front view of a main part of an unsteady aerodynamic force measuring device for a wind tunnel test according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a vibration applying method in the first embodiment.
In the correspondence diagram, (A) shows when vertical vibration is applied, and (B) shows when rotational vibration is applied.

FIG. 3 is a view as viewed in the direction of arrows AA in FIG. 1;

FIG. 4 is a main part front view showing a second embodiment.

FIG. 5 is a diagram corresponding to FIG. 1 showing a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Frame 1a Upper member 1b Lower member 1c Side member 2 Support 4, 04 Spring 5 Connecting member 6 Drive link 7 Crank 9 Guide rail 10 Motor 11 Frame support 12 Bearing 13 Rail mount 14 Rotation stand 15 Model rotation center 20 Load cell 21, 22 Connecting part 30 Linear motor 31 Support cable 32 Spherical joint part 100 Model 101 Air flow path 200 Support device

Claims (6)

[Claims] 1. A model disposed in an air flow space such as a wind tunnel through which air flows, is mounted on a frame connected to a vibration means, and the vibration means applies vibration to the model via the frame. An aerodynamic force measuring device for measuring an aerodynamic force acting on the model by an air flow through a load cell, wherein the model is suspended from the frame via an elastic supporting member, and the load cell is attached to the frame. An apparatus for measuring aerodynamic force, wherein the apparatus is installed at a lower part of a model, and the lower part of the model is connected to the load cell. 2. The aerodynamic measuring device according to claim 1, wherein said elastic support member is constituted by a spring interposed between said frame and an upper portion of said model. 3. The linear support according to claim 1, wherein the elastic support member is a linear motor attached to an upper portion of the frame and having an output end connected to an upper portion of the model.
An aerodynamic measuring device as described. 4. The frame is vertically movable and rotatable around a central axis of the model and is supported on a fixed member, and the frame is vertically moved by the vibrating means via a drive link mechanism or the central shaft. 2. The aerodynamic measuring device according to claim 1, wherein the measuring device is configured to be rotated around. 5. A connecting portion between the drive link mechanism and the frame is movable, and the position of the connecting portion is changed, so that the frame and the model can be moved through the vibrating means and the drive link mechanism. 5. The aerodynamic force measuring device according to claim 4, wherein a vertical movement or a rotation around the central axis is selectable. 6. A model provided in an air flow space such as a wind tunnel through which air flows, is attached to a frame connected to a vibration means, and the vibration means applies vibration to the model via the frame. A method of measuring an air force acting on the model by an air flow through a load cell, wherein the model is suspended from the frame via an elastic support member, and the weight of the model is supported by the elastic support. A method of measuring aerodynamic force, wherein the method is supported by a member, the lower part of the model is connected to the load cell, and the aerodynamic force generated in the model is mainly applied to the load cell.