JPH06213764A - Ground face simulator for wind tunnel - Google Patents

Abstract

PURPOSE:To allow accurate simulation of flying state or running state by eliminating the border layer developing on a ground face plate simulating the ground face in wind tunnel test. CONSTITUTION:The ground face simulator for wind tunnel comprises a ground face plate 19 simulating the ground face having a microporous surface 1 and a unit(suction pump 4) for sucking a border layer 13 on the ground plate 19 through micropores. The border layer 13 developing on the ground plate 19 is sucked uniformly and extinguished.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wind tunnel ground simulator applied to a wind tunnel test of an aircraft, a hovercraft, a vehicle or the like which is flying or traveling near the ground.

[0002]

2. Description of the Related Art A first example of a conventional wind tunnel ground simulator will be described with reference to FIG. In this device, the wind tunnel air flow 1
In the wind tunnel 11 in which 0 flows, a smooth plate, that is, a ground plate 14, is installed to simulate the ground, and the aircraft model 12 is installed near the ground plate 14 and close thereto. However, this apparatus cannot obtain the same test conditions as the actual machine because the boundary layer 13 which is not present during flight and running of the actual machine occurs from the tip of the ground plate 14.

A second example of a conventional wind tunnel ground simulation device,
This will be described with reference to FIGS. 7 and 8. In this device, the suction nozzle 16 discontinuous in the flow direction of the surface of the blow-out type ground plate 24 (see FIG. 7) or the suction-type ground plate 25 (see FIG. 8).
Alternatively, a suction nozzle 17 is provided and a jet is blown out from the nozzle or the boundary layer 13 is sucked to reduce the boundary layer on the blowing-type ground plate 24 or the suction-type ground plate 25. The aircraft model 12 is installed close to above the blow-out type ground plate 24 or the suction type ground plate 25. However, in this device, since the nozzles 16 and 17 are discontinuous,
The boundary layer 13 cannot be eliminated uniformly on the ground plate 14.

A third example of a conventional wind tunnel ground simulator will be described with reference to FIG. In this device, the ground is simulated by a belt 15 that moves at the same speed as the wind tunnel airflow 10. The aircraft model 12 is installed above and near the belt 15.
This device is ideal because no boundary layer occurs on the belt 15, but it is difficult to move the belt 15 at high speed without distortion or vibration, and the wind tunnel test is limited to low wind tunnel wind speed.

[0005]

In a wind tunnel test, when a ground plate 14 is installed as shown in FIG. 6 in order to simulate the ground, a boundary layer 13 is always generated on the surface of the ground plate 14, and the boundary layer is located downstream. The layer thickness increases. However, there is no boundary layer on the ground under actual flight conditions or vehicle traveling conditions because the actual aircraft or the vehicle itself moves.

Therefore, in the wind tunnel test, the ground plate 14
It is necessary to eliminate the upper boundary layer and create the same flight and running conditions as in reality.

It is difficult to eliminate the boundary layer on the ground plate uniformly in the conventional device for blowing and sucking in the nozzle as shown in FIG. 7 and FIG.
The device using the moving belt 15 shown in (1) cannot perform a high-speed wind tunnel test.

The present invention is intended to provide a ground tunnel simulator for a wind tunnel which solves the above-mentioned problems of the conventional technique.

[0009]

SUMMARY OF THE INVENTION A ground tunnel simulator for a wind tunnel according to the present invention comprises a ground plate simulating the ground having a porous surface having a large number of fine holes, and a boundary layer formed on the ground plate. It is characterized in that it is provided with a suction device for sucking through.

[0010]

In the present invention, the boundary layer on the ground plate is sucked through the fine holes on the porous surface by the suction device. On this occasion,
Since a large number of fine holes are provided on the porous surface, the boundary layer is uniformly sucked over the entire area of the porous surface, and the boundary layer disappears.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIG. The upper surface of the ground plate 19, which is provided in the wind tunnel and is arranged substantially parallel to the wind tunnel airflow 10, and which simulates the ground, is the boundary layer 1
It is formed by a porous surface 1 having a large number of fine holes on its entire surface in order to suck in 3. Below the porous surface 1, the wind tunnel airflow 10
A chamber 2 divided in the flow direction is provided. The chamber 2 is connected to a suction pump 4 via a suction duct 9, and a plurality of valves 3 for setting the suction flow rate from each chamber 2 are provided between the chamber 2 and the suction duct 9. The opening degree of the valve 3 is set by the valve controller 8 according to an instruction from the computer 7.

On the other hand, several skewer-type total pressure tubes 5 are set on the ground plate 19 in the flow direction of the wind tunnel airflow 10 (1 in FIG. 1).
(A book is shown), the signal of the skewer type total pressure pipe 5 is the ground plate 19
The pressure converter 6 provided inside measures the total pressure distribution in the boundary layer 13, and the signal of the pressure converter 6 is input to the computer 7 to calculate the velocity distribution in the vertical direction of the ground plate 19. It has become. The computer 7 determines the suction flow rate of the porous surface 1 so that there is no vertical velocity gradient at any position of the skewer-shaped total pressure pipe 5, and outputs a signal designating the opening of the valve 3 to the valve controller 8.

The porous surface 1 having fine pores on the surface of the ground plate 19 is provided with perforations having a diameter of approximately 0.1 mm and a pitch of 1 mm, and the boundary layer 13 on the ground plate 19 is uniformly distributed in the chamber 2. The boundary layer 13 is made to disappear by sucking into. Further, the chamber 2 is sized so as to have a sufficient volume for sucking the boundary layer 13 uniformly from the porous surface 1.

In the present embodiment constructed as described above, a model such as an aircraft is placed at a position near and above the ground plate 19, and the wind tunnel airflow 10 is made to flow. The boundary layer 13 developed on the porous surface 1 of the ground plate 19 is sucked by the suction pump 4 through the fine holes of the porous surface 1 and the suction duct 9, so that the boundary layer 13 can be eliminated. At this time, the porous surface 1 has a large number of fine holes, and the boundary layer 13 can be sucked uniformly over the entire area of the porous surface 1.

Further, the pressure converter 6 calculates the vertical velocity distribution of the boundary layer 13 on the ground plate 19 in accordance with the signals of several skewer-shaped total pressure tubes 5 provided in the flow direction of the wind tunnel airflow 10, The signal from the pressure converter 6 is input to the computer 7, and the computer 7 determines the suction amount of the porous surface 1 so that the vertical velocity gradient disappears, that is, the boundary layer 13 disappears, and this signal is output to the valve controller. 8 to control the opening of the valve 3 of each chamber 2. The boundary layer 13 that develops on the porous surface 1 gradually increases in thickness on the downstream side in the flow direction, but as described above, the chambers 2 that are divided in the flow direction are provided, and several layers are provided in the flow direction. By controlling the opening degree of the valve 3 of each chamber 2 based on the signal of the skewer-shaped total pressure pipe 5, the boundary layer 13 can be surely eliminated in the entire region on the porous surface 1.

Further, in this embodiment, since the chamber 2, the valve 3 and the like are provided in the ground plate 19 and are connected to the suction pump 4 through the suction duct 9, they are portable.
It can be applied to any wind tunnel.

An example of use of this embodiment is shown in FIG. Wind tunnel 1
The ground plate 19 is installed in 1 in parallel with the wind tunnel air flow 10,
A vehicle model 18 is arranged close to above the ground plate 19 to perform a wind tunnel test while the vehicle is running.

Another example of use of this embodiment is shown in FIG. In this case as well, a ground plate is installed in the wind tunnel 11 substantially parallel to the wind tunnel air flow, and is placed close to above the ground plate 19 and is close to the aircraft half model 20.
To place.

In the wind tunnel test, a semi-model test method has been established in which, when the model becomes excessively large, it is divided into two parts by the plane of body symmetry and the divided surface is set on the wind tunnel floor. However, this method has a problem that the aerodynamic force acting on the model is not half that of the whole model due to the boundary layer developing on the floor surface of the wind tunnel. However, FIG.
As shown in FIG. 7, if the present embodiment is used, the boundary layer on the ground plane is eliminated, and the above problems can be eliminated.

A second embodiment of the present invention will be described with reference to FIG. In this embodiment, a part of the floor surface of the wind tunnel 11 is a porous surface 1, and a chamber, a valve, a suction duct, a suction pump, a skewer-type total pressure pipe, a pressure converter below the porous surface 1 are provided. As the computer, the valve controller 8 and the like, those having the same configurations as those of the first embodiment are adopted.

This embodiment has the same operation and effect as the first embodiment, but in addition to this, the time required for setting the ground plate is unnecessary because the ground plate becomes a part of the wind tunnel equipment. can do.

FIG. 5 shows the effects of the first and second embodiments. The vertical axis of FIG. 5 represents the lift of the machine body, and the horizontal axis represents the attitude angle of the machine body. Normally, the lift of an aircraft near the ground increases under the same attitude and angle conditions compared to when flying above the ground. However, in the conventional device, the change in lift becomes large due to the influence of the boundary layer 13 on the ground plate. However, when the ground plate 19 having the porous surface according to the first and second embodiments is used, as shown in FIG. 5, data closer to flight test data can be obtained.

Therefore, in the first and second embodiments, the flight characteristics of the actual aircraft can be accurately estimated from the wind tunnel test data, and the aircraft design with high reliability can be realized.

[0024]

INDUSTRIAL APPLICABILITY According to the present invention, in a wind tunnel ground simulating device, a boundary layer that develops on the ground plate through a large number of fine holes on the porous surface of the ground plate is made uniform by a device having a simple structure, The suction can be effectively performed, the influence of the boundary layer on the ground plate can be eliminated in the wind tunnel test, and the state of flight of the aircraft, traveling of the vehicle, etc. can be accurately simulated.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view of a first embodiment of the present invention.

FIG. 2 is a vertical sectional front view of a usage example of the first embodiment.

FIG. 3 shows another usage example of the first embodiment, and FIG.
3A is a vertical sectional front view thereof, and FIG. 3B is a vertical sectional side view thereof.

FIG. 4 is a vertical sectional front view of a second embodiment of the present invention.

FIG. 5 is a graph showing the relationship between the lift force and the aircraft attitude angle in the first and second embodiments of the present invention, together with the conventional ground plate, the case without a ground plate, and flight test data.

FIG. 6 is a vertical sectional front view showing a ground plate of a conventional wind tunnel ground simulation device.

FIG. 7 is a vertical cross-sectional front view of a conventional wind tunnel ground simulation device having a blow-out type ground plate.

FIG. 8 is a vertical cross-sectional front view of a wind tunnel ground simulator having a conventional suction-type ground plate.

FIG. 9 is a vertical sectional front view of a wind tunnel ground simulation device having a conventional belt-type ground plate.

[Explanation of symbols]

 1 Porous Surface 2 Chamber 3 Valve 4 Suction Pump 5 Skew Type Total Pressure Tube 6 Pressure Transducer 7 Computer 8 Bubble Controller 9 Suction Duct 10 Wind Tunnel Air Flow 11 Wind Tunnel 12 Aircraft Model 13 Boundary Layer 14 Ground Plate 15 Belt 16 Blowout Nozzle 17 Suction Nozzle 18 Vehicle model 19 Ground plate 20 Aircraft half model 23 Belt type ground plate 24 Blowing type ground plate 25 Suction type ground plate

Claims (1)

[Claims] 1. A ground plate simulating the ground having a porous surface having a large number of fine holes, and a suction device for sucking a boundary layer generated on the ground plate through the fine holes. Wind tunnel ground simulator.