JPH0823517B2 - Transonic flutter stop device in wind tunnel test. - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wind tunnel test device for an elastic aircraft model, and more particularly to a device for performing a flutter wind tunnel test in the transonic region.

[0002]

2. Description of the Related Art In the transonic region, there is a possibility that airframes are irregularly excited and flutter occurs in the airframe, leading to destruction. It was necessary to confirm the characteristics of this region in a wind tunnel test. However, in the flutter experiment in the wind tunnel test, generally, the aircraft model is instantly destroyed by the occurrence of flutter. Therefore, unless the flutter is stopped immediately after the flutter occurs to protect the test body, it is necessary to replace with a new model each time the test is performed, and it is difficult to perform a sufficient test. As a method of stopping the flutter of the test body, there are a method of bypassing the collecting tunnel and the measurement unit, and a method of taking the test body out of the wind tunnel. However, both methods require large-scale auxiliary equipment in the wind tunnel main body and require a long time to operate. In addition, the method of putting it out has a long span, and a wing with complicated support or mounting may be damaged by the impact of starting and stopping the operating part.

[0003]

In order to carry out a high-speed flutter wind tunnel test in the transonic region safely, surely, with high precision and efficiency without destroying the model, the above problems do not occur. The flutter stop device is required as an accessory facility for the wind tunnel. And such a flutter stop device can be installed without changing the basic structure and performance of the wind tunnel main body, and as soon as flutter occurs on the blade, it automatically lowers the Mach number and dynamic pressure to below the limit value. There must be.

[0004]

DISCLOSURE OF THE INVENTION A flutter stop device of the present invention is a flutter stop portion having an air flow shielding effect in a wind tunnel having an extraction chamber for a flutter test in a transonic region.
Measure the material at a position where the wake of the stop member does not hit the specimen.
It is characterized in that the flutter stop member is stored in a wall surface of a fixed part and the flutter stop member is inserted into the measuring part in response to a flutter generation signal from a flutter detection device.

[0005]

The flutter stopping member stored at an arbitrary position on the wall surface of the measuring portion of the transonic wind tunnel having the bleeding chamber operates the actuator immediately by the signal of the sensor attached to the wing model, and automatically the flutter stopping member. Is inserted into the measuring section. Depending on the ratio of the cross-sectional area of the flutter stop member inserted in the measuring section and the cross-sectional area of the measuring section of the wind tunnel, the Mach number and the dynamic pressure are instantaneously changed by the energy loss of the wind tunnel due to the resistance and the bleeding action that circulates into the bleeding chamber. Decrease below the flutter limit.
This allows wing flutter to be stopped safely and reliably.

[0006]

The present invention will be described in more detail with reference to the following examples. FIG. 1 is a perspective view showing the overall configuration of the flutter stop device of the present invention. The side wall of the extraction chamber 8 of the measurement unit 1 of the transonic wind tunnel has an acrylic observation window 8'on one side and a porous wall 8 "on the other side to perform the extraction action. Strain gauge 5 for response detection attached to the wing
Is provided. A flutter stop member 2 having a bleeding action as a perforated plate is normally stored on the bottom surface, and when the strain gauge 5 detects the occurrence of flutter, the actuator 6 is activated and the flutter stop member 2 is inserted. Then, due to the resistance, the Mach number and the dynamic pressure are instantly lowered below the flutter limit value. The degree of this decrease can be adjusted by the area of the flutter stop member 2. In the figure, 10 is a pitot tube.

Since this flutter stop does not utilize the wake of the flutter stop member 2, it is located on the front surface of the wing model and it is not necessary to cover it. Therefore, the wing model 3 and the flutter stop member 2 are arranged. Can be arbitrarily selected. In the embodiment shown in FIG. 2, when the wing model and the flutter stop device are installed on the upper surface of the measurement part and the flutter stop device on the bottom surface of the transonic wind tunnel, respectively, the wing model and the flutter stop device are installed on the same surface of the bottom face of the measurement part in the embodiment shown in FIG. Shown when installed. In the embodiment shown in FIG. 3, if the body of the wing model overhangs and it is difficult to install the flutter stop device, two stop members may be installed separately on both sides of the body. In the figure, 3'is a wing model support bracket, 4 is a blind lid, 7
Is a controller, 9 is a potentiometer, and the upright state of the flutter stop member 2 is indicated by a dotted line.

The Mach number reduction rate due to such a flutter stop member is expressed as follows, where Fp is the cross-sectional area of the flutter stop member and Fw is the cross-sectional area of the wind tunnel.

[Equation 1] Proportional to

[Equation 2] It is represented by. The amount of decrease ΔM is shown in FIG. In the figure, ○ indicates
When (Fp / Fw) = 0.0533 in the arrangement of ∇, ▽ is shown in FIG.
Shows the case where (Fp / Fw) = 0.0161 in the arrangement.

FIG. 5 shows the arrangement of Mach 0.
The flutter stop effect in the case of the test in 79 is shown, (a) shows the operation signal of the flutter stop member, (b) shows the response signal of the blade, and (c) shows the pressure signal of the measurement part. Due to the insertion of the flutter stop, the flutter stop is seen almost at the same time as the pressure signal begins to drop.

[0010]

As described above, the flutter stopping device of the present invention automatically operates the flutter stopping member when flutter is generated, and can stop flutter instantly. High-speed flutter test can be performed safely and reliably without breaking the model. In addition, since the wake of the flutter stop member is not used, it can be installed at any position in the measurement unit in the wind tunnel, and even if there is a body etc., it can be installed at a position avoiding the sample to obtain a flutter stop effect. You can Therefore, it is possible to install the wind tunnel as an accessory to the existing one without restraining the model and without damaging the characteristics of the wind tunnel. 2 and 3 of the above embodiment,
The flutter stop member is normally configured to be stored in parallel with the wall surface and is configured to stand up during operation, but in FIG. 1, the member is slid and inserted into the measurement unit. It can be changed.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing an overall configuration of an embodiment of a flutter stop device of the present invention.

FIG. 2 is a conceptual diagram showing an arrangement of a model and a flutter stop device in another embodiment of the flutter stop device of the present invention.

FIG. 3 is a conceptual diagram showing an arrangement of a model and a flutter stop device in still another embodiment of the flutter stop device of the present invention.

FIG. 4 is a graph showing a Mach number reduction rate of the flutter stopping device of the present invention.

FIG. 5 shows signals from various parts showing a stopping effect of the flutter stopping device of the present invention.

[Explanation of symbols]

1 Wind tunnel measurement unit 2 Flutter stop member 3
Wing model with simulated fuselage 4 Blind lid 5 Strain gauge for response detection 6
Actuator 7 Controller 8 Extraction chamber 9
Potentiometer 10 Pitot tube

Front Page Continuation (72) Inventor Koichi Suzuki 2-2-17-205 Daimoncho, Higashi-Kurume City, Tokyo (72) Inventor Masataka Masataka 4-78-3 Chuo, Musashimurayama City, Tokyo (56) References Special Kai 63-94130 (JP, A)

Claims (1)

[Claims] 1. A wind tunnel having an extraction chamber for a flutter test in a transonic region, in which a flap having an air flow shielding effect is provided.
The stopper stop member, the wake of the stop member does not hit the specimen.
At a position, the transonic flutter stop device in a wind tunnel test is characterized in that the flutter stop member is stored in the measurement part wall surface and the flutter stop member is inserted into the measurement part in response to a flutter generation signal from the flutter detection device.