JP5107865B2 - Fluctuating wind generator and wind tunnel device - Google Patents

Description

  The present invention relates to a fluctuating wind generator and a wind tunnel device.

  A wind tunnel device is used for measuring the acoustic performance of an automobile, for example, wind noise generated around the automobile. In order to measure the above-mentioned wind noise and the like, it is required to reduce other sounds, for example, the sound generated by the wind tunnel device (noise reduction).

  In recent years, the wind noise of automobiles due to fluctuating winds that vary in wind speed and direction, such as natural winds, has been seen as a problem, so the relationship between fluctuating winds and wind noises has been clarified and appropriate low noise levels for automobiles. There is a need to make it easier.

In order to clarify the relationship between such fluctuating wind and wind noise, a wind tunnel device capable of producing fluctuating wind has been proposed (see, for example, Patent Document 1).
Specifically, a plurality of blade rows and dampers are installed at the nozzle outlet of the wind tunnel, and fluctuating wind close to natural wind is created by controlling the direction of the blade rows and the like.
Japanese Utility Model Publication No.59-020140

However, the wind tunnel device described in Patent Document 1 described above has a problem in that characteristic noise is generated in a plurality of blade rows, dampers, and the like when fluctuating wind is generated.
Characteristic noise is significant noise of a specific frequency component that appears due to the influence of acoustic eigenvalues between blade rows or between dampers due to the hydrodynamic excitation force generated by the blade rows or dampers. Characteristic noise includes inter-blade resonance, duct resonance in a wind tunnel device, noise due to vibration of blades, and the like. Hereinafter, characteristic noise is referred to as ringing.

  The squeal is a very high level of noise compared to the background noise caused by the air current of the wind tunnel device itself, so there is a problem that it is impossible to measure the wind noise generated around the car when squeak occurs. there were.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a fluctuating wind generator and a wind tunnel device capable of generating fluctuating wind and reducing generated noise. .

In order to achieve the above object, the present invention provides the following means.
The variable wind generator according to the present invention extends in a direction crossing an air flow direction, and controls at least one control plate for controlling the air flow by flowing air along a surface, and a longitudinal direction of the control plate And a drive unit that controls the angle of attack of the control plate with respect to the air flow direction. The control plate transmits at least sound waves in the audible band. It has the property.

According to the present invention, since the control board has sound permeability, for example, the acoustic boundary between the wall surface arranged around the control board and the control board or between the plurality of control boards becomes ambiguous. That is, since there is no acoustic eigenvalue between a plurality of control plates, it is possible to suppress the generation of sound that is affected by the acoustic eigenvalue.
In particular, since the control version transmits sound waves in the audible band, it is possible to suppress at least the generation of sound corresponding to sound waves in the audible band.

  Since the control plate controls the flow of air by flowing air along the surface, it is possible to suppress noise generated by the flow, such as scratching noise and airflow noise.

  When the angle of attack of the control plate with respect to the above-described air flow (hereinafter referred to as airflow) is changed by the driving unit, the direction of the airflow or the passage area of the airflow changes, so that the flow velocity of the airflow changes. By changing the angle of attack of the control plate with the passage of time, the flow velocity and direction of the air flow will change with the passage of time, and a fluctuating wind with a varying wind speed and direction like natural wind will be added to the air flow. Can do.

  In the above invention, the control plate forms at least a part of the outer shape of the control plate, and has a plate-like porous member in which a plurality of through-holes are formed; A thin film member disposed so as to transmit vibrations of gas molecules constituting air on the side to the gas molecules constituting air on the other surface side and to cover at least the plurality of through holes. desirable.

According to the present invention, since the sound wave propagating toward the control plate passes through the thin film member covering the through hole and the through hole of the porous member, the control plate can exhibit sound permeability.
Since the thin film member prevents air from passing therethrough, the thin film member is disposed so as to cover the opening of the through hole from the outside, thereby preventing the airflow flowing along the control plate from flowing into the through hole. Thereby, the airflow flows along the control plate, and the controllability of the airflow in the control plate can be ensured. Furthermore, since the turbulence of the airflow generated by the airflow flowing into the through hole is suppressed, the noise generated by the turbulence of the flow can be suppressed low.

  The size and arrangement of the through holes formed in the porous member are preferably determined based on the frequency or wavelength of the sound wave transmitted through the control plate (for example, the frequency or wavelength of the audible band). The aperture ratio, which is a value divided by the member area, is desirably about 30% or more. By setting the through hole in this way, sound waves can pass through the porous member (control plate) through the through hole.

Even if the thin film member prevents air from passing therethrough, it allows the transmission of sound waves by transmitting the movement of gas molecules such as nitrogen and oxygen on one side of the thin film member to the gas molecule on the other side. Can do.
Examples of a material for forming such a thin film member include resins such as polyvinylidene chloride, polyethylene, and polyvinyl chloride, but the material is not particularly limited. The thickness of the thin film member is desirably a thickness that can realize the softness capable of transmitting the above-described movement of gas molecules from one surface side to the other surface side.
When the thin film member is disposed so as to cover the opening of the through hole from the outside, the tension applied to the thin film member is soft enough to allow the thin film member to transmit the movement of the gas molecules from one surface side to the other surface side. It is desirable that the tension be such that the thin film member does not generate hydrodynamic characteristics such as an increase in flow resistance, a change in flow direction, and hydrodynamic noise due to sagging of the thin film member.

  In the above invention, it is preferable that a film-like surface protection member that allows air and sound waves to pass therethrough is provided on at least a surface of the control plate where the thin film member is in contact with the air flow.

According to the present invention, the sound wave propagating toward the control plate is transmitted through the surface protection member, and the transmitted sound wave is transmitted through the thin film member covering the through hole and the through hole of the porous member. Can demonstrate its sexuality.
Since the surface protection member covers a surface (hereinafter referred to as a surface) in contact with the air flow in the thin film member, the surface unevenness of the surface of the thin film member due to the through hole is covered by the surface protection member. Since the above-mentioned unevenness does not appear on the surface of the surface protection member, the turbulence of the airflow flowing along the control plate can be suppressed, and the noise generated by the turbulence of the airflow can be suppressed low.

  Examples of the surface protection member include a cloth-like member formed by weaving fibers, and it is desirable that the opening ratio, which is a value obtained by dividing the total gap area of the fibers by the fiber area, is about 30% or more. By doing so, since the sound wave can pass through the surface protection member, even if tension is applied and the surface protection member is disposed on the surface of the thin film member, the sound transmission is not lowered like the thin film member. . By arranging the surface protection member under tension, it is possible to prevent the unevenness due to the through holes from appearing on the surface of the surface protection member.

  Since the surface protection member also covers unevenness of the surface due to wrinkles and the like formed on the thin film member, it is possible to suppress turbulence of the air flow due to wrinkles and the like, and to suppress noise generated by the turbulence of the air flow. This can reduce the labor for removing irregularities such as wrinkles when the thin film member is disposed on the porous member.

  In the above invention, it is desirable that the control plate is provided with a plate-like non-woven member formed by forming at least a part of the outer shape of the control plate and combining the fibrous members.

According to the present invention, since the sound wave propagating toward the control plate passes through the gap between the fibrous members in the non-woven member, the control plate can exhibit sound permeability.
The gap between the fibrous members in the non-woven member is narrow and the flow path resistance is high. Therefore, the airflow is less likely to permeate the nonwoven member and flows along the control plate, so that controllability of the airflow in the control plate can be ensured.

Furthermore, since the unevenness on the contact surface (surface) between the control plate and the air flow is smaller than that of the control plate in which the porous member and the thin film member are combined, the control plate has no loss of sound transmission. The flow on the surface can be rectified, and the increase in resistance and the generation of sound (airflow sound) due to the flow affected by unevenness can be suppressed.
In addition, as a fibrous member, the synthetic fiber formed from natural fiber, resin, etc., a metal fiber, etc. can be illustrated.

  In the above-mentioned invention, it is desirable that a thin film member that prevents the transmission of air and allows the transmission of sound waves is provided on at least the surface of the control plate where the nonwoven member contacts the air flow.

According to the present invention, the sound wave propagating toward the control plate is transmitted through the thin film member and the non-woven member that covers the surface of the non-woven member in contact with the air flow (hereinafter referred to as the surface). The control plate can exhibit sound transparency.
By covering the surface of the non-woven member with the thin film member, it is possible to block a slight flow of air that passes through the gaps of the non-woven member. Therefore, it is possible to prevent the airflow controllability of the control plate from being deteriorated due to the above-described permeation of the airflow.

  In the above invention, it is desirable that a surface in contact with the air flow is provided with a film-like surface protection member that allows air and sound waves to pass therethrough.

According to the present invention, the sound wave propagating toward the control plate passes through the surface protection member, and the transmitted sound wave passes through the thin film member and the non-woven member, or passes through the non-woven member. Sound permeability can be exhibited.
Since the surface protection member covers the surface of the thin film member or the surface of the non-woven member, the unevenness on the surface of the thin film member or the non-woven member is covered by the surface protection member. Since the irregularities do not appear on the surface of the surface protection member, it is possible to suppress turbulence of air flowing along the control plate and to suppress hydrodynamically generated noise to a low level.

  A wind tunnel device according to the present invention includes the fluctuating wind generator according to the present invention.

According to the present invention, by providing the fluctuating wind generator of the present invention, there is no acoustic eigenvalue in the fluctuating wind generating apparatus, and the generation of sound that is affected by the acoustic eigenvalue is suppressed.
A fluctuating wind whose wind speed and direction fluctuate like natural wind is added to the air flow passing through the fluctuating wind generator of the present invention.

According to the fluctuating wind generator and the wind tunnel device of the present invention, since the control plate has sound permeability, there is no acoustic eigenvalue between a plurality of control plates, etc., and the generation of sound affected by the acoustic eigenvalue can be suppressed. There is an effect that the generated noise can be reduced.
Since the angle of attack of the control plate with respect to the airflow is changed by the drive unit, there is an effect that it is possible to create a fluctuating wind in which the wind speed and the wind direction fluctuate like the natural wind.

[First Embodiment]
Hereinafter, a wind tunnel device according to a first embodiment of the present invention will be described with reference to FIGS.
Drawing 1 is a mimetic diagram explaining the composition near the blower outlet in the wind tunnel device concerning this embodiment.
As shown in FIG. 1, the wind tunnel device 1 includes a duct 3 through which air having a uniform flow velocity flows, a contracted portion 5 in which the flow path area of the duct 3 is reduced, and an airflow flowing out from the contracted portion 5 ( And a fluctuating wind generator 7 for controlling the flow velocity and direction of the air flow).

FIG. 2 is a schematic diagram illustrating the configuration of the fluctuating wind generator of FIG.
The fluctuating wind generator 7 controls the support housing 9, a blade row formed from a plurality of blades (control plates) 11 that change the flow velocity of the passing airflow, and the angle of attack of the plurality of blades 11 with respect to the airflow. A drive unit 13 is provided.

The support housing 9 is a member that constitutes the frame of the fluctuating wind generator 7, and the blade row of the blades 11 and the drive unit 13 are disposed therein.
The wing 11 is a plate-like member disposed so as to extend in a direction orthogonal to the airflow passing through the fluctuating wind generator 7, and controls the airflow by flowing air along the periphery of the wing 11. Is.

FIG. 3 is a schematic diagram for explaining the configuration of the blades constituting the blade row portion of FIG. 2. 4 is an AA cross-sectional view of the wing for explaining the internal configuration of the wing of FIG. FIG. 5 is a BB cross-sectional view of the wing for explaining the internal configuration of the wing of FIG. 3.
As shown in FIGS. 3 to 5, the wing 11 includes a leading edge member 15, a trailing edge member 17 and a wing tip member 19 which are members constituting the frame of the wing 11, and a girder disposed inside the wing 11. A member 21, a porous plate (porous member) 23 constituting the upper and lower surfaces of the wing 11, and a thin film sheet (thin film member) 25 covering the outer surface of the wing 11 are provided.

The leading edge member 15 is a frame member that constitutes the leading edge of the blade 11, and the shape of the leading edge of the blade 11 and the shape of the vicinity of the leading edge on the upper and lower surfaces of the blade 11 are formed.
The trailing edge member 17 is a frame member that constitutes the trailing edge of the blade 11, and the shape of the trailing edge of the blade 11 and the shape of the vicinity of the trailing edge on the upper and lower surfaces of the blade 11 are formed.
The blade tip member 19 is a frame member that constitutes the end of the blade 11.

  The girder member 21 is a plate-like member extending from the leading edge member 15 to the trailing edge member 17, and is a member that supports the porous plate 23 disposed on the upper surface and the lower surface of the blade 11. The girder member 21 is formed with screw holes 29 for fixing the porous plate 23 to the girder member 21 by screwing screws 27.

The perforated plate 23 is a plate-like member that constitutes most of the upper and lower surfaces of the blade 11. A plurality of sound transmission holes (through holes) 31 are formed in the porous plate 23, and the plurality of sound transmission holes 31 are arranged in a staggered manner.
The number and the hole area of the sound transmission holes 31 are determined so that the ratio of the total area of the sound transmission holes 31 to the area of the porous plate 23, that is, the aperture ratio is 30% or more. The arrangement interval of the sound transmission holes 31 and the like are determined based on the band of sound transmitted through the wing 11, and in the present embodiment, are determined so as to transmit sound in the audible band.
For example, the perforated plate 23 can have a thickness of several mm, and the sound transmission hole 31 can have a diameter of about 2.5 mm to 8 mm.

The thin film sheet 25 is a thin film member that covers the outer surface of the wing 11 including the porous plate 23, and in particular, is a thin film member that covers the sound transmission holes 31 formed in the porous plate 23. The thin film sheet 25 blocks the transmission of air and allows the transmission of sound waves, particularly sound waves in the audible band.
The thin film sheet 25 is affixed to the wing 11 using an adhesive, and a predetermined tension is applied to the thin film sheet 25 during the affixing to prevent the formation of irregularities such as wrinkles on the surface of the wing 11. The tension applied to the thin film sheet 25 is a tension that can prevent the thin film sheet 25 from sagging into the sound transmission hole 31 and is in a tension range that does not inhibit transmission of sound waves in the audible band.

  By preventing the formation of irregularities in this way, it is possible to prevent noise from being generated due to the disturbance of the airflow due to the irregularities. On the other hand, by making the applied tension to be a tension that can prevent the thin film sheet 25 from sagging into the sound transmission hole 31, vibration of the thin film sheet 25 when air flows around the wing 11 can be prevented. It is possible to prevent noise from being generated due to the turbulence of the airflow caused by the vibration of 25.

Examples of the material for forming the thin film sheet 25 include resins such as polyvinylidene chloride, polyethylene, polyvinyl chloride, polymethylbenten, and combinations thereof.
The film thickness of the thin film sheet 25 is set to a thickness that can ensure the flexibility of allowing the transmission of sound waves in the audible band. The film thickness of the thin film sheet 25 differs depending on the material forming the thin film sheet 25, the tension applied to the thin film sheet 25, the diameter of the sound transmission hole 31, and the like. For example, the thin film sheet 25 formed of polyvinylidene chloride When disposed so as to cover the sound transmission hole 31 having a diameter of 2.5 mm, a film thickness of 100 μm or less can be exemplified.

  A protective film formed of an adhesive or the like may be formed on the surface of the thin film sheet 25, and is not particularly limited.

FIG. 6 is a schematic diagram for explaining another embodiment of the fluctuating wind generator of FIG. FIG. 7 is a cross-sectional view illustrating the configuration of the damper of FIG.
The fluctuating wind generator 7 may generate fluctuating wind by the plurality of blades 11 as described above, or as shown in FIG. 6, the blade 11 and a flat plate damper (control plate) 11A. (Refer to FIG. 7) Fluctuating wind may be generated using both of them, or a plurality of dampers 11 </ b> A may be provided to generate fluctuating wind, and there is no particular limitation.

The drive unit 13 controls the angle of attack (phase) with respect to the airflow in the blade 11. As shown in FIG. 2, the drive unit 13 is provided with drive shafts 33A and 33B connected to the blade 11 and a phase control motor 35 connected to the drive shafts 33A and 33B.
The drive shaft 33 </ b> A is a shaft connected to the blade 11 on a one-to-one basis, and transmits the rotational driving force generated by the phase control motor 35 to the blade 11. The drive shaft 33 </ b> B is a shaft connected to a pair of adjacent blades 11, and transmits the rotational driving force generated by the phase control motor 35 to the pair of blades 11.

FIG. 8 is a schematic diagram for explaining an example of blade phase control. FIG. 9 is a schematic diagram illustrating another example of phase control.
The phase control motor 35 controls the direction of the airflow in the fluctuating wind generator 7 or the area of the flow path through which the airflow passes by controlling the angle of attack of the blade 11 via the drive shafts 33A and 33B.
For phase drive control by the phase control motor 35, as shown in FIG. 8, the same phase drive control for rotating the adjacent blades 11 in the same rotational direction and the adjacent damper 11A as shown in FIG. There is anti-phase drive control for rotating in the rotation direction.

Next, a method for generating fluctuating wind in the wind tunnel device 1 having the above configuration will be described.
As shown in FIG. 1, an air flow having a uniform flow velocity is formed in the duct 3 of the wind tunnel device 1, and the air flows into the fluctuating wind generator 7 through the contracted flow part 5. The airflow that has flowed into the fluctuating wind generator 7 is changed to a fluctuating wind whose flow velocity and direction change with time, and flows out toward the measurement region 37 of the wind tunnel device 1. A measurement object such as a car is arranged in the measurement area 37, and wind noise is measured.

In the fluctuating wind generator 7, as shown in FIG. 2, the angle of attack of the blade 11 is changed over time by the phase control motor 35 of the drive unit 13. Thereby, the direction of the airflow in the fluctuating wind generator 7 or the area of the flow path through which the airflow flows changes with time, and the flow rate and direction of the airflow blown out from the fluctuating wind generator 7 fluctuate with time. Wind is formed.
At this time, since the outer surface of the blade 11 is covered with the thin film sheet 25, the airflow flows around the blade 11 through the sound transmission hole 31 without passing through the blade 11.

  Note that the change in the flow velocity of the fluctuating wind may be a sinusoidal periodic change or an irregular change, and may be used properly depending on the purpose of measuring the wind noise.

Here, suppression of the sound generated from the fluctuating wind generator 7 which is a feature of the present embodiment will be described.
Sound waves incident from the upper surface or the lower surface of the blade 11 pass through the thin film sheet 25 and the sound transmission holes 31 without being reflected by the thin film sheet 25 or the perforated plate 23.
Sound waves propagate in the air as vibrations of gas molecules and collide with the thin film sheet 25. The thin film sheet 25 moves due to collision of gas molecules, and pushes and vibrates the gas molecules on the opposite surface. Therefore, the sound wave can pass through the thin film sheet 25.
Since the sound transmission holes 31 are disposed in the perforated plate 23 corresponding to the audible band, the sound wave does not recognize the perforated plate 23 as a wall and passes through the wing 11 through the sound transmission holes 31.

Next, the result of the sound measurement experiment in the fluctuating wind generator 7 according to the present embodiment will be described.
FIG. 10 is a graph showing the relationship between the frequency of the sound generated from the fluctuating wind generator and the sound pressure level.
FIG. 10 is formed from a porous plate 23 having an aperture ratio of 42% in which sound transmission holes 31 having a diameter of 2.5 mm are arranged in a staggered manner, and a thin film sheet 25 having a thickness of less than 100 μm formed of polyvinylidene chloride. In the fluctuating wind generator 7 using the wing 11, the sound measurement result when the flow velocity of the airflow is 40 m / s is shown.

In FIG. 10, a graph A is a measurement result of the fluctuating wind generation device 7 according to the above-described embodiment, and a graph Z is a measurement result of the fluctuating wind generation device using a conventional blade having no sound permeability.
As shown in the graph Z, the significant sound peak (sounding peak) between 1000 Hz and 10000 Hz generated in the conventional variable wind generator is the variable wind generator 7 according to the present embodiment. (See graph A), it can be seen that the generation of sound is suppressed.

  The graph B is a graph showing the measurement result of the fluctuating wind generator 307 according to the third embodiment to be described later, and the graph B will be described in the description of the third embodiment.

FIG. 11 is a sonagraph showing the relationship between the frequency of sound generated from a conventional fluctuating wind generator and the sound pressure level, along with changes in the flow velocity of the airflow.
FIG. 11 shows a measurement result of the sound generated from the conventional fluctuating wind generator using wings having no sound permeability when the flow velocity of the airflow is changed from 0 m / s to 50 m / s. Yes. As can be seen from the sonagraph of FIG. 11, the conventional fluctuating wind generator generates a sound (sound) ZS having a high sound pressure level whose frequency changes in proportion to the flow velocity of the airflow.

FIG. 12 is a sonagraph showing the relationship between the frequency of sound generated from the fluctuating wind generator of this embodiment and the sound pressure level, along with the change in the flow velocity of the airflow.
On the other hand, the measurement result of the sound generated from the fluctuating wind generator 7 according to this embodiment under the same conditions is shown as a sonagraph in FIG. As can be seen from the sonagraph of FIG. 12, it can be seen that in the fluctuating wind generator 7, the sound ZS is not generated and the generation of sound is suppressed.

According to said structure, since the wing | blade 11 has sound permeability, the acoustic boundary between the wall surface of the support housing | casing 9 arrange | positioned around the wing | blade 11 and the wing | blade 11, or between several wing | blades 11 is used, for example. Becomes ambiguous. That is, since there is no acoustic eigenvalue in the cascade composed of a plurality of wings 11, it is possible to suppress the generation of sound that is affected by the acoustic eigenvalue.
In particular, since the wing 11 transmits sound waves in the audible band, it is possible to suppress at least the generation of sound corresponding to sound waves in the audible band.

  Since the airfoil 11 controls the airflow by flowing air along the surface, noise generated by the flow, for example, scratching noise can be suppressed to a low level.

  When the angle of attack of the blade 11 with respect to the airflow is changed by the driving unit, the direction of the airflow or the passage area of the airflow changes, so that the flow velocity of the airflow changes. By changing the angle of attack of the blades 11 with the passage of time, the direction of the air flow or the flow velocity of the air flow changes with the passage of time, and a fluctuating wind whose wind speed and direction change like natural wind is added to the air flow. be able to.

Since the sound wave propagating toward the wing 11 passes through the thin film sheet 25 covering the sound transmission hole 31 and the sound transmission hole 31 of the perforated plate 23, the wing 11 can exhibit sound transmission.
In order for the thin film sheet 25 to block air permeation, the thin film sheet 25 is disposed so as to cover the opening of the sound transmission hole 31 from the outside, so that the airflow flowing along the blades 11 flows into the sound transmission hole 31. Can be prevented. As a result, the airflow flows along the wing 11, and the controllability of the airflow in the wing 11 can be ensured. Furthermore, since the turbulence of the airflow generated by the airflow flowing into the sound transmission hole 31 is suppressed, the noise generated by the turbulence of the flow can be suppressed low.

  Even if the thin film sheet 25 prevents the permeation of air, it allows the transmission of sound waves by transmitting the movement of gas molecules such as nitrogen and oxygen on one side of the thin film sheet 25 to the gas molecule on the other side. can do.

[First Modification of First Embodiment]
Next, a first modification of the first embodiment of the present invention will be described with reference to FIG.
The basic configuration of the wind tunnel device of the present modification is the same as that of the first embodiment, but the configuration of the blades in the variable wind generator is different from that of the first embodiment. Therefore, in this modification, only the configuration of the wing will be described with reference to FIG. 13, and description of other components and the like will be omitted.
FIG. 13 is a cross-sectional view illustrating the configuration of the blades in the fluctuating wind generator of the present modification.
In addition, about the component same as 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  As shown in FIG. 13, the blade (control plate) 111 of the fluctuating wind generator 107 includes a leading edge member 15, a trailing edge member 17, a blade edge member 19, which are members constituting the blade 111, and the blade 111. , A perforated plate 23 that constitutes the upper and lower surfaces of the wing 111, a thin film sheet 25 that covers the surface of the wing 111, and a surface material (surface protection member) 127. .

The surface material 127 is a film-like member arranged so as to form the surface of the wing 111 on the outer side of the thin film sheet 25. As the surface material 127, a material having an aperture ratio of 30% or more and a thickness of less than 500 μm, for example, a cloth such as a cold candy can be used. The opening ratio when the cloth is used as the surface material 127 is calculated based on the gap between the fibers.
In addition, as the surface material 127, it is desirable that unevenness due to the sound transmission hole 31 of the porous plate 23 can be prevented from appearing on the surface of the blade 111. By selecting such a surface material 127, it is possible to prevent the generation of noise caused by the turbulence of the air flow due to the above-described unevenness.

A method for generating a fluctuating wind in the fluctuating wind generating apparatus having the above configuration will be described.
In the fluctuating wind generator 107, as in the first embodiment, the angle of attack of the blades 111 is changed by the phase control motor 35 over time, and the flow velocity and direction of the airflow blown out from the fluctuating wind generator 107 are changed. A fluctuating wind that varies with time is formed.
At this time, air flows along the surface material 127 that covers the surface of the wing 111. Therefore, the airflow is prevented from being disturbed by unevenness due to wrinkles of the thin film sheet 25 or the like.

Here, suppression of the sound generated from the fluctuating wind generator 107, which is a feature of the present embodiment, will be described.
The sound wave incident from the upper surface or the lower surface of the wing 111 first passes through the surface material 127. Since the surface material 127 has an aperture ratio of 30% or more, sound waves can pass through the surface material 127.
As for the thin film sheet 25 and the sound transmission hole 31, as described in the first embodiment, sound waves incident from the upper surface or the lower surface of the wing 111 are transmitted through the wing 111.

  According to the above configuration, the sound wave propagating toward the wing 111 passes through the surface material 127, and the transmitted sound wave passes through the thin film sheet 25 covering the sound transmission hole 31 and the sound transmission hole 31 of the porous plate 23. Therefore, the wing 111 can exhibit sound permeability, and can suppress the sound generated in the cascade composed of the wing 111.

  Since the surface material 127 covers the surface of the thin film sheet 25, the unevenness on the surface of the thin film sheet 25 caused by the sound transmission holes 31 is covered with the surface material 127. Since the above-described unevenness does not appear on the surface of the surface material 127, the disturbance of the airflow flowing along the blade 111 can be suppressed, and the noise generated by the disturbance of the flow can be suppressed to a low level.

  Since a cloth such as a cold chill having an aperture ratio of 30% or more is used as the surface material 127, sound waves can pass through the surface material 127. Therefore, even if the surface material 127 is placed on the surface of the thin film sheet 25 under tension, the sound transmission is not lowered like the thin film sheet 25. By disposing the surface material 127 under tension, it is possible to prevent the unevenness due to the sound transmission holes 31 from appearing on the surface of the surface material 127 and to suppress the noise generated by the flow disturbance.

  Since the surface material 127 also covers surface irregularities due to wrinkles and the like formed on the thin film sheet 25, it is possible to suppress turbulence of the air flow due to wrinkles and the like, and to suppress noise generated due to the turbulence of the air flow. Therefore, the labor for removing irregularities such as wrinkles when placing the thin film sheet 25 on the porous plate 23 is reduced, and the process of applying the thin film sheet 25 becomes easy.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIGS.
The basic configuration of the wind tunnel device of this embodiment is the same as that of the first embodiment, but the configuration of the blades in the variable wind generator is different from that of the first embodiment. Therefore, in the present embodiment, only the configuration of the wing will be described using FIGS. 14 to 17, and description of other components and the like will be omitted.
FIG. 14 is a schematic diagram for explaining the configuration of the blades in the fluctuating wind generator of the present embodiment. FIG. 15 is a cross-sectional view illustrating the configuration of the wing of FIG.
In addition, about the component same as 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  As shown in FIGS. 14 and 15, the blade (control plate) 211 of the fluctuating wind generator 207 includes a leading edge member 15, a trailing edge member 17, and a blade tip member 19 which are members constituting the frame of the blade 211. A girder member 21 disposed inside the wing 211 and a resin non-woven plate (non-woven member) 223 constituting the upper and lower surfaces of the wing 211 are provided.

The resin non-woven board 223 is a plate-like member in which resin fibers (fibrous members) are laminated and bonded, and a gap is formed between the resin fibers. The resin nonwoven plate 223 constitutes most of the upper and lower surfaces of the wing 211.
In the present embodiment, the surface roughness of the resin nonwoven plate 223 is handled as being approximately the diameter of the resin fiber.

A method for generating a fluctuating wind in the fluctuating wind generating apparatus having the above configuration will be described.
In the fluctuating wind generator 207, as in the first embodiment, the angle of attack of the blades 211 is changed over time by the phase control motor 35, and the flow velocity and direction of the airflow blown out from the fluctuating wind generator 207 are changed. A fluctuating wind that varies with time is formed.
At this time, part of the air flowing around the blades 211 flows into the gaps between the resin fibers in the resin nonwoven plate 223, but the flow rate of the gaps is high, so the inflow rate is small. Therefore, most of the air flows around the wing 211.

Here, suppression of the sound generated from the fluctuating wind generator 207, which is a feature of the present embodiment, will be described.
Sound waves incident from the upper surface or the lower surface of the blade 211 pass through the resin nonwoven plate 223 through the gaps between the resin fibers in the resin nonwoven plate 223. Then, the acoustic boundary in the wing 211 becomes ambiguous, and the acoustic eigenvalue between the wings 211 disappears.
By eliminating the acoustic eigenvalue, the sound generated in the cascade composed of the blades 211 is suppressed.

According to the above configuration, since the sound wave propagating toward the wing 211 passes through the gap between the resin fibers in the resin non-woven plate 223, the wing 211 can exhibit sound permeability. It is possible to suppress the noise generated in the cascade.
The gap between the resin fibers in the resin nonwoven plate 223 is narrow and the flow path resistance is high. For this reason, the airflow is less likely to permeate the resin nonwoven plate 223 and flows along the wing 211, so that controllability of the airflow in the wing 211 can be ensured.

  Compared with the blade 11 in the first embodiment, the unevenness formed on the surface of the blade 211 is reduced, so that the air flow on the surface of the blade 211 can be rectified without impairing the sound permeability of the blade 211. it can. Therefore, it is possible to suppress an increase in resistance in the blade 211 and generation of a new airflow sound.

FIG. 16 is a cross-sectional view illustrating the configuration of another embodiment according to the wing of FIG.
Note that the upper and lower surfaces of the blades 211 may be formed from the resin nonwoven plate 223 as in the above-described embodiment, or the thin film sheet 25 is attached to the surface of the resin nonwoven plate 223 as shown in FIG. It may be attached and is not particularly limited.
By comprising in this way, it can block | prevent that an airflow permeate | transmits the wing | blade 211 through the micro clearance gap of the resin nonwoven board 223, and the airflow controllability of the wing | blade 211 falls by permeation | transmission of the above-mentioned airflow. Can be prevented.

FIG. 17 is a cross-sectional view illustrating the configuration of still another embodiment according to the wing of FIG.
Furthermore, as shown in FIG. 17, a thin film sheet 25 may be stretched on the surface of the resin nonwoven plate 223, and a surface material 127 may be further adhered thereon, or a surface material 127 may be adhered on the surface of the resin nonwoven plate 223. There is no particular limitation.
By configuring as shown in FIG. 17, it is possible to suppress the roughness of the surface of the blade 211, and without impairing the sound transmittance as compared with the blade 211 in which the resin nonwoven plate 223 forms the surface, The airflow on the surface of the blade 211 can be rectified. For this reason, it is possible to suppress noise generated due to an increase in flow resistance and turbulence in the airflow.

[Third Embodiment]
Next, a third embodiment of the present invention will be described with reference to FIGS.
The basic configuration of the wind tunnel device of this embodiment is the same as that of the first embodiment, but the configuration of the blades in the variable wind generator is different from that of the first embodiment. Therefore, in the present embodiment, only the configuration of the wing will be described using FIGS. 18 to 21, and the description of the other components and the like will be omitted.
FIG. 18 is a cross-sectional view illustrating the configuration of the blades in the fluctuating wind generator of this embodiment.
In addition, about the component same as 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  As shown in FIG. 18, the blade (control plate) 311 of the fluctuating wind generator 307 includes a leading edge member 15, a trailing edge member 17, a blade edge member 19, and blades 311 which are members constituting the blade 311. A girder member 21 disposed inside the wing 311 and a metal non-woven plate (non-woven member) 323 constituting the upper and lower surfaces of the wing 311 are provided.

The metal non-woven plate 323 is a plate-like member in which metal fibers (fibrous members) are laminated and bonded, and a gap is formed between the metal fibers and the metal fibers. The metal non-woven plate 323 constitutes most of the upper and lower surfaces of the wing 311.
Examples of the metal non-woven plate 323 include a plate (for example, Altone (registered trademark)) formed from an aluminum fiber nonwoven fabric formed from metal fibers obtained by fiberizing aluminum by a melt spinning method.
In the present embodiment, the surface roughness of the metal non-woven plate 323 is handled as being about the diameter of the metal fiber.

A method for generating a fluctuating wind in the fluctuating wind generating apparatus having the above configuration will be described.
In the fluctuating wind generator 307, as in the first embodiment, the angle of attack of the blade 311 is changed over time by the phase control motor 35, and the flow velocity and direction of the airflow blown from the fluctuating wind generator 307 are changed. A fluctuating wind that varies with time is formed.
At this time, a part of the air flowing around the blade 311 flows into the gap between the metal fibers in the metal non-woven plate 323, but the flow rate of the gap is high, so the inflow rate is small. Therefore, most of the air flows around the wing 311.

Here, suppression of the sound generated from the fluctuating wind generator 307, which is a feature of the present embodiment, will be described.
A sound wave incident from the upper surface or the lower surface of the wing 311 passes through the gap between the metal fibers in the metal nonwoven plate 323 and passes through the metal nonwoven plate 323. Then, the acoustic boundary in the wing 311 becomes ambiguous, and the acoustic eigenvalue between the wings 311 disappears.
By eliminating the acoustic eigenvalue, the sound generated in the cascade composed of the blades 311 is suppressed.

Next, the result of the sound measurement experiment in the fluctuating wind generator 307 according to the present embodiment will be described.
In the fluctuating wind generator 307 using the above-described blade 311, the sound measurement result when the air flow velocity is 40 m / s is shown as a graph B in FIG. 10.

  Compared with the graph A which is the measurement result of the fluctuation wind generator 7 in the first embodiment and the graph Z which is the measurement result of the conventional fluctuation wind generator, the fluctuation wind generator 307 of the present embodiment is 1000 Hz. It can be seen that the sound level (sounding sound level) in the band of 10000 Hz is the lowest.

FIG. 19 is a sonagraph showing the relationship between the frequency of sound generated from the fluctuating wind generator of FIG. 18 and the sound pressure level, along with the change in air flow velocity.
As can be seen from the measurement result of the sound generated from the fluctuating wind generator 307 when the air flow rate is changed from 0 m / s to 50 m / s (see FIG. 19), the sound whose frequency changes in proportion to the air flow rate. The sound (sound) ZS (see FIG. 10) with a high pressure level is not generated from the fluctuating wind generator 307.

According to the above configuration, the sound wave propagating toward the wing 311 passes through the gap between the metal fibers in the metal non-woven plate 323, so that the wing 311 can exhibit sound permeability. It is possible to suppress the noise generated in the cascade.
The gap between the resin fibers in the metal nonwoven plate 323 is narrow and the flow path resistance is high. For this reason, since air hardly permeates the metal nonwoven plate 323 and air flows along the wing 311, controllability of air flow in the wing 311 can be ensured.

  Compared with the wing 11 in the first embodiment and the wing 211 in the second embodiment, the unevenness formed on the surface of the wing 311 is reduced, so that the sound transmission of the wing 311 is not impaired. The air flow on the surface can be rectified. Therefore, it is possible to suppress an increase in resistance in the blade 311 and generation of a new airflow sound.

  Compared to the blade 211 using the resin nonwoven plate 223, the blade 311 of the present embodiment uses the metal nonwoven plate 323 having high mechanical strength, so that the mechanical strength of the blade 311 is increased. Therefore, the driving force for generating the fluctuating wind can be reliably transmitted to the wing 311 and the deformation of the wing 311 due to the drag acting on the wing 311 can be suppressed. This can be done more reliably.

FIG. 20 is a cross-sectional view illustrating the configuration of another embodiment according to the wing of FIG.
As in the above-described embodiment, the upper and lower surfaces of the wing 311 may be formed from the metal nonwoven plate 323, or the thin film sheet 25 is attached to the surface of the metal nonwoven plate 323 as shown in FIG. It may be attached and is not particularly limited.
By comprising in this way, it can block | prevent that airflow permeate | transmits the wing | blade 311 through the micro clearance gap of the metal nonwoven board 323, and the airflow controllability of the wing | blade 311 falls by permeation | transmission of the above-mentioned airflow. Can be prevented.

FIG. 21 is a cross-sectional view illustrating the configuration of still another embodiment according to the wing of FIG.
Furthermore, as shown in FIG. 21, the thin film sheet 25 may be stretched on the surface of the metal non-woven plate 323, and the surface material 127 may be further stuck thereon, which is not particularly limited.
By configuring as shown in FIG. 21, the roughness of the surface of the wing 311 can be suppressed, and compared with the wing 311 where the metal non-woven plate 323 forms the surface, without impairing the sound transmittance, The airflow on the surface of the blade 311 can be rectified. For this reason, it is possible to suppress noise generated due to an increase in flow resistance and turbulence in the airflow.

It is a schematic diagram explaining the structure of the blower outlet vicinity in the wind tunnel apparatus which concerns on the 1st Embodiment of this invention. It is a schematic diagram explaining the structure of the fluctuating wind generator of FIG. It is a schematic diagram explaining the structure of the wing | blade which comprises the blade cascade part of FIG. It is AA sectional drawing of the wing | blade explaining the internal structure of the wing | blade of FIG. It is a BB sectional view of a wing explaining the internal composition of the wing of Drawing 3. It is a schematic diagram explaining the other Example of the fluctuating wind generator of FIG. It is sectional drawing explaining the structure of the damper of FIG. It is a schematic diagram explaining an example of the phase control of a wing | blade. It is a schematic diagram explaining the other example of phase control. It is a graph which shows the relationship between the frequency of the sound which generate | occur | produces from a fluctuating wind generator, and a sound pressure level. It is a sonograph which shows the relationship between the frequency of the sound which generate | occur | produces from the conventional fluctuating wind generator, and a sound pressure level with the change of an air flow velocity. It is a sonograph which shows the relationship between the frequency of the sound and the sound pressure level which generate | occur | produce from the fluctuating wind generator of this embodiment with the change of an air flow velocity. It is sectional drawing explaining the structure of the blade | wing in the fluctuating wind generator which concerns on the 1st modification of the 1st Embodiment of this invention. It is a schematic diagram explaining the structure of the wing | blade in the fluctuating wind generator of the 2nd Embodiment of this invention. It is sectional drawing explaining the structure of the wing | blade of FIG. It is sectional drawing explaining the structure of another Example which concerns on the wing | blade of FIG. It is sectional drawing explaining the structure of another Example which concerns on the wing | blade of FIG. It is sectional drawing explaining the structure of the wing | blade in the fluctuating wind generator of the 3rd Embodiment of this invention. FIG. 19 is a sonagraph showing the relationship between the frequency of sound generated from the fluctuating wind generator of FIG. 18 and the sound pressure level, along with changes in air flow velocity. It is sectional drawing explaining the structure of another Example which concerns on the wing | blade of FIG. It is sectional drawing explaining the structure of another Example which concerns on the wing | blade of FIG.

Explanation of symbols

1 Wind tunnel device 7, 107, 207, 307 Fluctuating wind generator 11, 111, 211, 311 Wing (control plate)
11A damper (control board)
13 Drive unit 23 Perforated plate (porous member)
25 Thin film sheet (thin film member)
31 Sound transmission hole (through hole)
127 Surface material (surface protection member)
223 Resin non-woven board (non-woven member)
323 Nonwoven metal sheet (nonwoven material)

Claims (3)

At least one control plate extending in a direction crossing the air flow direction and controlling the air flow by flowing air along the surface;
A drive unit that rotates the control plate around an axis along the longitudinal direction of the control plate and controls the angle of attack of the control plate with respect to the air flow direction; and
The control plate may have a sound transmission that transmits sound waves of at least audible range,
The control plate includes
A plate-like porous member that forms at least a part of the outer shape of the control plate and has a plurality of through holes;
Arranged to prevent the permeation of air and transmit the vibration of the gas molecules constituting the air on one side to the gas molecules constituting the air on the other side, covering at least the plurality of through holes A thin film member;
Is provided,
A fluctuating wind generating device characterized in that a film-like surface protection member that allows air and sound waves to pass through is provided on at least a surface of the control plate where the thin film member is in contact with the air flow . At least one control plate extending in a direction crossing the air flow direction and controlling the air flow by flowing air along the surface;
A drive unit that rotates the control plate around an axis along the longitudinal direction of the control plate and controls the angle of attack of the control plate with respect to the air flow direction; and
The control plate may have a sound transmission that transmits sound waves of at least audible range,
The control plate includes
A plate-like non-woven member formed by forming at least a part of the outer shape of the control plate and combining the fibrous members;
A thin film arranged to prevent the permeation of air and transmit vibrations of gas molecules constituting air on one surface side to gas molecules constituting air on the other surface side so as to cover at least the nonwoven member Members,
Is provided,
A fluctuating wind generating device characterized in that a film-like surface protection member that allows air and sound waves to pass through is provided on at least a surface of the control plate where the thin film member is in contact with the air flow . Wind tunnel apparatus comprising: a fluctuation wind generator according to claim 1 or 2.

Images