Device and method for automatically adjusting airflow pulsation speed along with wind speed change

Abstract

The invention relates to a device and a method for automatically adjusting airflow pulsation speed along with wind speed change. The device comprises a grating blade, a grating blade mounting frame mechanism, a grating blade horizontal righting mechanism, a grating blade flapping wing vibration executing mechanism and a grating blade flapping wing amplitude adjusting mechanism, the grating blade mounting rack mechanism is fixedly arranged in the wind tunnel; the grating blades are arranged on the grating blade mounting frame mechanism; the grating blade horizontal righting mechanism is positioned above the wind tunnel and is connected with the grating blade mounting rack mechanism; the grating blade flapping wing vibration executing mechanism is located below the wind tunnel, and the grating blade flapping wing amplitude adjusting mechanism is arranged on the grating blade flapping wing vibration executing mechanism and connected with the grating blades through a transmission connecting rod. According to the invention, the replacement process of a traditional damping net, a grating and the like is omitted, the test efficiency and the normalization are improved, the airflow pulsation speed can be automatically adjusted according to the wind speed change, the purpose of keeping the turbulence basically constant under different wind speed conditions is achieved, and the accuracy and the reliability of test data are effectively improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of wind tunnel testing, and in particular relates to a device and method for automatically adjusting airflow pulsation speed as wind speed changes. Background Art

[0002] Low-speed wind tunnels are essential for aerodynamic research, and the quality of their flow fields directly impacts the credibility of test data from aircraft, automobiles, and architectural models. Turbulence, a core flow field parameter, requires precise control based on various test scenarios, such as laminar airfoil testing and atmospheric boundary layer simulations. Turbulence must also be maintained low and stable throughout the entire test.

[0003] Turbulence intensity is expressed as the ratio of the root mean square (RMS) velocity to the time-averaged velocity. The time-averaged velocity represents the steady-state portion of the flow, ignoring transient fluctuations caused by turbulence. In wind tunnel testing, the time-averaged velocity can remain constant even in the presence of turbulence. Fluctuating velocity represents the random fluctuations of energy in turbulence. Even in wind tunnel testing, even when the time-averaged velocity is stable, localized fluctuations can occur due to factors such as detached vortices and shear layers.

[0004] At present, traditional turbulence control technology relies heavily on damping nets, grilles, etc. Under the same wind speed conditions, it is necessary to adjust the turbulence by replacing the damping nets, grilles, etc., so there are problems such as troublesome replacement, reduced test efficiency, and poor normalization. If the damping nets, grilles, etc. are not replaced, the turbulence will decrease with the increase of wind speed, thereby affecting the accuracy and reliability of the test data. Summary of the Invention

[0005] In response to the problems existing in the prior art, the present invention provides a device and method for automatically adjusting the airflow pulsation speed as the wind speed changes, eliminating the need to replace traditional damping nets, grilles, etc., and can effectively improve the test efficiency and normalization. It can automatically adjust the airflow pulsation speed according to the wind speed changes in the wind tunnel, thereby achieving the purpose of keeping the turbulence basically constant under different wind speed conditions, and effectively improving the accuracy and reliability of the test data.

[0006] In order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a device for automatically adjusting the airflow pulsation speed as the wind speed changes, comprising grille blades, a grille blade mounting frame mechanism, a grille blade horizontal straightening mechanism, a grille blade flapping vibration actuator and a grille blade flapping amplitude adjustment mechanism; the grille blade mounting frame mechanism is fixedly installed in the wind tunnel; there are a number of grille blades, and a number of grille blades are evenly spaced along the height direction of the wind tunnel on the grille blade mounting frame mechanism, and the extension direction ends of the leading edge sides of all grille blades are connected in series by a transmission connecting rod, and the grille blades and the transmission connecting rod are hinged; the grille blade horizontal straightening mechanism is located above the wind tunnel, and the grille blade horizontal straightening mechanism is connected to the grille blade mounting frame mechanism; the grille blade flapping vibration actuator is located below the wind tunnel, and the grille blade flapping amplitude adjustment mechanism is arranged on the grille blade flapping vibration actuator, and the grille blade flapping amplitude adjustment mechanism is connected to the transmission connecting rod.

[0007] The grille blade mounting frame mechanism includes a guide static slide rail and a lifting movable slide rail; the guide static slide rail is vertically fixed on the inner surface of the wind tunnel side wall plate; the lifting movable slide rail is vertically inserted into the guide static slide rail, and the lifting movable slide rail only has a linear lifting freedom relative to the guide static slide rail, and the lifting movable slide rail passes through the wind tunnel top wall plate upward; the end of the leading edge side of the grille blade in the extension direction is hinged on the lifting movable slide rail.

[0008] The horizontal righting mechanism of the grille blade includes a righting motor, a screw rod, a nut and a force transmission plate; the righting motor is vertically fixed above the wind tunnel, and the motor shaft of the righting motor faces downward; the upper end of the screw rod is coaxially fixedly connected to the motor shaft of the righting motor through a coupling, and the lower end of the screw rod is rotatably connected to the outer surface of the top wall plate of the wind tunnel through a bearing seat; the nut is sleeved on the screw rod, and the nut is fixedly connected to the force transmission plate; the force transmission plate is horizontally arranged, and the end of the force transmission plate is fixedly connected to the upper end of the lifting slide rail.

[0009] The grille blade flapping vibration actuator includes a flapping vibration actuator motor and a rotating disc; the flapping vibration actuator motor is horizontally fixed below the wind tunnel; the rotating disc is vertically arranged, and the center of the rotating disc is fixedly connected to the motor shaft of the flapping vibration actuator motor.

[0010] The grille blade flapping amplitude adjustment mechanism includes a flapping amplitude adjustment motor, a gear, a rack, a slider, a guide rail and a force transmission rod; the guide rail is fixedly mounted on the surface of the rotating disc, the guide rail is radially distributed along the rotating disc, one end of the guide rail is located at the center of the rotating disc, and the other end of the guide rail is located at the edge of the rotating disc; the slider is mounted on the guide rail, and the slider has only linear movement freedom relative to the guide rail; the flapping amplitude adjustment motor is fixedly mounted on the slider, and the motor shaft of the flapping amplitude adjustment motor is distributed perpendicular to the guide rail; one end of the force transmission rod is hinged to the housing of the flapping amplitude adjustment motor, and the other end of the force transmission rod is hinged to the bottom end of the transmission connecting rod; the rack is fixedly mounted on the surface of the rotating disc, and the rack is distributed parallel to the guide rail; the gear is coaxially fixed on the motor shaft of the flapping amplitude adjustment motor, and the gear is meshed with the rack.

[0011] A method for automatically adjusting airflow pulsation speed according to wind speed changes, using the device for automatically adjusting airflow pulsation speed according to wind speed changes, comprises the following steps:

[0012] Step 1: Set the flapping amplitude of the grille blades. First, start the flapping vibration actuator motor to drive the rotating disc to rotate until the guide rail is in a vertical state and located on the upper half of the rotating disc;

[0013] Step 2: Start the flapping wing amplitude adjustment motor to drive the gear to rotate. The gear's rotary motion will be synchronously converted into rolling motion along the rack, thereby driving the flapping wing amplitude adjustment motor and the slider to move linearly along the guide rail until the transmission link is driven upward by half the flapping wing amplitude through the force transmission rod. At this time, the grille blades will deflect around their hinge point with the lifting slide rail, causing the grille blades to change from a horizontal state to a downward deflection state;

[0014] Step 3: Start the righting motor to drive the screw to rotate. The rotary motion of the screw will be synchronously converted into the linear motion of the nut. The nut will drive the force transmission plate to move downward synchronously, and then drive the lifting movable slide rail to move upward along the guide static slide rail. At the same time, it drives the grille blade to deflect around the hinge point with the transmission connecting rod until the grille blade returns to the horizontal state from the downward deflection state.

[0015] Step 4: Select a test point in the center of the wind tunnel test section and install a hot wire probe at the selected test point. The distance between the test point and the grille blade should be no less than 10 times the chord length of the grille blade.

[0016] Step 5: Start the wind tunnel and adjust the wind speed to the set value. Then, the hot wire probe at the test point measures the airflow pulsation velocity in real time. The measured airflow pulsation velocity is then converted into airflow turbulence.

[0017] Step 6: Start the flapping vibration actuator motor to drive the rotating disc to rotate. The rotating disc drives the transmission connecting rod to make up and down reciprocating motion through the force transmission rod, thereby driving the grille blades to make flapping motion around the hinge point between them and the lifting slide rail;

[0018] Step 7: Changing the speed of the flapping vibration actuator motor to adjust the flapping vibration frequency of the grille blades to change the airflow pulsation speed, thereby changing the airflow turbulence until the measured airflow turbulence is consistent with the set target turbulence;

[0019] Step 8: Repeat steps 1 to 7, except that the wind speed setting value remains unchanged, and the flapping amplitude setting value of the grille blades and the target turbulence setting value are changed;

[0020] Step 9: Repeat steps 1 to 8, but adjust the wind speed setting value.

[0021] Step 10: Establish a database of wind speed, grille blade flapping amplitude, grille blade flapping vibration frequency, and target turbulence;

[0022] Step 11: When conducting a wind tunnel test, input the target turbulence. According to the change in wind speed, the corresponding grille blade flapping amplitude and grille blade flapping vibration frequency are automatically matched from the database, so that the airflow turbulence in the wind tunnel is automatically adjusted to the target value.

[0023] Beneficial effects of the present invention:

[0024] The device and method of the present invention for automatically adjusting the airflow pulsation speed as the wind speed changes eliminate the need for replacing traditional damping nets, grilles, etc., can effectively improve test efficiency and normalization, and can automatically adjust the airflow pulsation speed according to the wind speed changes in the wind tunnel, thereby achieving the purpose of keeping the turbulence basically constant under different wind speed conditions, effectively improving the accuracy and reliability of test data. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A front view of a device for automatically adjusting airflow pulsation speed according to wind speed changes according to the present invention;

[0026] Figure 2 A side view of a device for automatically adjusting airflow pulsation speed according to wind speed changes according to the present invention;

[0027] Figure 3 It is a front view of the grille blade flapping amplitude adjustment mechanism of the present invention;

[0028] Figure 4 It is a side view of the combination of the grille blade flapping amplitude adjustment mechanism and the grille blade flapping vibration actuator of the present invention;

[0029] In the figure, 1 is the grille blade, 2 is the transmission connecting rod, 3 is the wind tunnel, 4 is the guide static slide rail, 5 is the lifting movable slide rail, 6 is the straightening motor, 7 is the lead screw, 8 is the nut, 9 is the force transmission plate, 10 is the flapping wing vibration actuator motor, 11 is the rotating disc, 12 is the flapping wing amplitude adjustment motor, 13 is the gear, 14 is the rack, 15 is the slider, 16 is the guide rail, and 17 is the force transmission rod. DETAILED DESCRIPTION

[0030] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] like Figures 1 to 4 As shown, a device for automatically adjusting the airflow pulsation speed as the wind speed changes, includes a grille blade 1, a grille blade mounting frame mechanism, a grille blade horizontal straightening mechanism, a grille blade flapping vibration actuator and a grille blade flapping amplitude adjustment mechanism; the grille blade mounting frame mechanism is fixedly installed in a wind tunnel 3; there are a plurality of grille blades 1, and a plurality of grille blades 1 are evenly spaced along the height direction of the wind tunnel 3 on the grille blade mounting frame mechanism, and the extension direction ends of the leading edge sides of all grille blades 1 are connected in series by a transmission connecting rod 2, and the grille blades 1 and the transmission connecting rod 2 are hinged; the grille blade horizontal straightening mechanism is located above the wind tunnel 3, and the grille blade horizontal straightening mechanism is connected to the grille blade mounting frame mechanism; the grille blade flapping vibration actuator is located below the wind tunnel 3, and the grille blade flapping amplitude adjustment mechanism is arranged on the grille blade flapping vibration actuator, and the grille blade flapping amplitude adjustment mechanism is connected to the transmission connecting rod 2.

[0032] The grille blade mounting frame mechanism includes a guide static slide rail 4 and a lifting movable slide rail 5; the guide static slide rail 4 is vertically fixed on the inner surface of the side wall panel of the wind tunnel 3; the lifting movable slide rail 5 is vertically inserted into the guide static slide rail 4, and the lifting movable slide rail 5 has only a linear lifting freedom relative to the guide static slide rail 4, and the lifting movable slide rail 5 passes through the top wall panel of the wind tunnel 3 upward; the end of the leading edge side of the grille blade 1 in the extension direction is hinged on the lifting movable slide rail 5.

[0033] The horizontal righting mechanism of the grille blade includes a righting motor 6, a screw rod 7, a nut 8 and a force transmission plate 9; the righting motor 6 is vertically fixed above the wind tunnel 3, and the motor shaft of the righting motor 6 faces downward; the upper end of the screw rod 7 is coaxially fixedly connected to the motor shaft of the righting motor 6 through a coupling, and the lower end of the screw rod 7 is rotatably connected to the outer surface of the top wall plate of the wind tunnel 3 through a bearing seat; the nut 8 is sleeved on the screw rod 7, and the nut 8 is fixedly connected to the force transmission plate 9; the force transmission plate 9 is horizontally arranged, and the end of the force transmission plate 9 is fixedly connected to the upper end of the lifting movable slide rail 5.

[0034] The grille blade flapping vibration actuator includes a flapping vibration actuator motor 10 and a rotating disc 11; the flapping vibration actuator motor 10 is horizontally fixed below the wind tunnel 3; the rotating disc 11 is vertically arranged, and the center of the rotating disc 11 is fixedly connected to the motor shaft of the flapping vibration actuator motor 10.

[0035] The grille blade flapping amplitude adjustment mechanism includes a flapping amplitude adjustment motor 12, a gear 13, a rack 14, a slider 15, a guide rail 16 and a force transmission rod 17; the guide rail 16 is fixedly mounted on the surface of the rotating disc 11, the guide rail 16 is distributed radially along the rotating disc 11, one end of the guide rail 16 is located at the center of the rotating disc 11, and the other end of the guide rail 16 is located at the edge of the rotating disc 11; the slider 15 is mounted on the guide rail 16, and the slider 15 has only linear movement freedom relative to the guide rail 16; The flapping-wing amplitude adjustment motor 12 is fixedly mounted on the slider 15, and the motor shaft of the flapping-wing amplitude adjustment motor 12 is perpendicularly distributed to the guide rail 16; one end of the force transmission rod 17 is hinged to the housing of the flapping-wing amplitude adjustment motor 12, and the other end of the force transmission rod 17 is hinged to the bottom end of the transmission connecting rod 2; the rack 14 is fixedly mounted on the surface of the rotating disc 11, and the rack 14 is parallel to the guide rail 16; the gear 13 is coaxially fixed on the motor shaft of the flapping-wing amplitude adjustment motor 12, and the gear 13 is engaged with the rack 14.

[0036] In this embodiment, the cross-sectional shape of the wind tunnel 3 is a rectangle of 1 m × 1.2 m, the maximum wind speed of the wind tunnel 3 is 50 m / s, the original turbulence of the wind tunnel 3 is 0.1%, the number of grille blades 1 is 18, the spacing between adjacent grille blades 1 is 50 mm, the chord length of the grille blade 1 is 200 mm, and the radius of the rotating disk 11 is 80 mm.

[0037] A method for automatically adjusting airflow pulsation speed according to wind speed changes, using the device for automatically adjusting airflow pulsation speed according to wind speed changes, comprises the following steps:

[0038] Step 1: Setting the flapping amplitude of the grille blade 1, first start the flapping vibration actuator motor 10, driving the rotary disc 11 to rotate until the guide rail 16 is in a vertical state and located at the upper half of the rotary disc 11;

[0039] Step 2: Start the flapping-wing amplitude adjustment motor 12 to drive the gear 13 to rotate. The rotary motion of the gear 13 will be synchronously converted into a rolling motion along the rack 14, thereby driving the flapping-wing amplitude adjustment motor 12 and the slider 15 to move linearly along the guide rail 16 until the transmission link 2 is driven upward by half the flapping-wing amplitude through the force transmission rod 17. At this time, the grille blade 1 will deflect around its hinge point with the lifting slide rail 5, causing the grille blade 1 to change from a horizontal state to a downward deflection state;

[0040] Step 3: Start the righting motor 6 to drive the screw rod 7 to rotate. The rotary motion of the screw rod 7 is synchronously converted into the linear motion of the nut 8, which drives the force transmission plate 9 to move downward synchronously through the nut 8, thereby driving the lifting movable slide rail 5 to move upward along the guide static slide rail 4, and at the same time drives the grille blade 1 to deflect around the hinge point between it and the transmission link 2 until the grille blade 1 returns to the horizontal state from the downward deflection state;

[0041] Step 4: Select a test point at the center of the test section of the wind tunnel 3 and install a hot wire probe at the selected test point. The distance between the test point and the grille blade 1 must be no less than 10 times the chord length of the grille blade 1. In this embodiment, the distance between the test point and the grille blade 1 is 2000 mm.

[0042] Step 5: Start wind tunnel 3 and adjust the wind speed to the set value. Then, the hot wire probe at the test point measures the airflow pulsation velocity in real time, and then simultaneously converts the measured airflow pulsation velocity into airflow turbulence.

[0043] Step 6: Start the flapping vibration actuator motor 10 to drive the rotating disc 11 to rotate. The rotating disc 11 drives the transmission connecting rod 2 to perform up and down reciprocating motion through the force transmission rod 17, thereby driving the grille blade 1 to perform flapping motion around the hinge point between the grille blade 1 and the lifting slide rail 5;

[0044] Step 7: Changing the speed of the flapping vibration actuator motor 10 to adjust the flapping vibration frequency of the grille blades 1 to change the airflow pulsation speed, thereby changing the airflow turbulence until the measured airflow turbulence is consistent with the set target turbulence;

[0045] Step 8: Repeat steps 1 to 7, except that the wind speed setting value remains unchanged, and the flapping amplitude setting value and the target turbulence setting value of the grille blade 1 are changed;

[0046] In this embodiment, the wind speed setting value is 10m / s;

[0047] When the target turbulence setting value is 0.2%, the flapping amplitude of the grille blade 1 is set to 3.2 mm, and the flapping vibration frequency of the grille blade 1 is 120 Hz;

[0048] When the target turbulence setting value is 0.4%, the flapping amplitude of the grille blade 1 is set to 12.4 mm, and the flapping vibration frequency of the grille blade 1 is 86 Hz;

[0049] When the target turbulence setting value is 0.6%, the flapping amplitude of the grille blade 1 is set to 20.6 mm, and the flapping vibration frequency of the grille blade 1 is 140 Hz;

[0050] When the target turbulence setting value is 0.8%, the flapping amplitude of the grille blade 1 is set to 26.8 mm, and the flapping vibration frequency of the grille blade 1 is 56 Hz;

[0051] When the target turbulence setting value is 1%, the flapping amplitude of the grille blade 1 is set to 30.2 mm, and the flapping vibration frequency of the grille blade 1 is 78 Hz;

[0052] When the target turbulence setting value is 1.2%, the flapping amplitude of the grille blade 1 is set to 32.8 mm, and the flapping vibration frequency of the grille blade 1 is 92 Hz;

[0053] When the target turbulence setting value is 1.4%, the flapping amplitude of the grille blade 1 is set to 34.4 mm, and the flapping vibration frequency of the grille blade 1 is 45 Hz;

[0054] When the target turbulence setting value is 1.6%, the flapping amplitude of the grille blade 1 is set to 35.6 mm, and the flapping vibration frequency of the grille blade 1 is 105 Hz;

[0055] When the target turbulence setting value is 1.8%, the flapping amplitude of the grille blade 1 is set to 37.4 mm, and the flapping vibration frequency of the grille blade 1 is 98 Hz;

[0056] When the target turbulence setting value is 2%, the flapping amplitude of the grille blade 1 is set to 38.2 mm, and the flapping vibration frequency of the grille blade 1 is 60 Hz;

[0057] Step 9: Repeat steps 1 to 8, but adjust the wind speed setting value.

[0058] In this embodiment, the adjusted wind speed setting values are 15m / s, 20m / s, 25m / s, 30m / s, 35m / s, 40m / s, 45m / s and 50m / s respectively;

[0059] Step 10: Establish a database of wind speed, flapping amplitude of grille blade 1, flapping vibration frequency of grille blade 1, and target turbulence;

[0060] Step 11: When conducting a wind tunnel test, the target turbulence is input. According to the change in wind speed, the corresponding flapping amplitude and flapping frequency of the grille blade 1 are automatically matched from the database, so that the airflow turbulence in the wind tunnel 3 is automatically adjusted to the target value.

[0061] The solutions in the embodiments are not intended to limit the scope of protection of the present invention. All equivalent implementations or modifications that do not depart from the scope of protection of the present invention are included in the scope of protection of the present invention.

Claims

1. A device for automatically adjusting airflow pulsation speed as wind speed changes, characterized by: It includes grille blades, a grille blade mounting frame mechanism, a grille blade horizontal straightening mechanism, a grille blade flapping vibration actuator and a grille blade flapping amplitude adjustment mechanism; the grille blade mounting frame mechanism is fixedly installed in the wind tunnel; there are a number of grille blades, and a number of grille blades are evenly distributed on the grille blade mounting frame mechanism along the height direction of the wind tunnel, and the extension direction ends of the leading edge sides of all grille blades are connected in series by a transmission connecting rod, and the grille blades and the transmission connecting rod are hinged; the grille blade horizontal straightening mechanism is located above the wind tunnel, and the grille blade horizontal straightening mechanism is connected to the grille blade mounting frame mechanism; the grille blade flapping vibration actuator is located below the wind tunnel, and the grille blade flapping amplitude adjustment mechanism is arranged on the grille blade flapping vibration actuator, and the grille blade flapping amplitude adjustment mechanism is connected to the transmission connecting rod.

2. The device for automatically adjusting airflow pulsation speed according to wind speed changes according to claim 1, characterized in that: The grille blade mounting frame mechanism includes a guide static slide rail and a lifting movable slide rail; the guide static slide rail is vertically fixed on the inner surface of the wind tunnel side wall plate; the lifting movable slide rail is vertically inserted into the guide static slide rail, and the lifting movable slide rail only has a linear lifting freedom relative to the guide static slide rail, and the lifting movable slide rail passes through the wind tunnel top wall plate upward; the end of the leading edge side of the grille blade in the extension direction is hinged on the lifting movable slide rail.

3. The device for automatically adjusting airflow pulsation speed according to wind speed changes according to claim 2, characterized in that: The horizontal righting mechanism of the grille blade includes a righting motor, a screw rod, a nut and a force transmission plate; the righting motor is vertically fixed above the wind tunnel, and the motor shaft of the righting motor faces downward; the upper end of the screw rod is coaxially fixedly connected to the motor shaft of the righting motor through a coupling, and the lower end of the screw rod is rotatably connected to the outer surface of the top wall plate of the wind tunnel through a bearing seat; the nut is sleeved on the screw rod, and the nut is fixedly connected to the force transmission plate; the force transmission plate is horizontally arranged, and the end of the force transmission plate is fixedly connected to the upper end of the lifting slide rail.

4. The device for automatically adjusting airflow pulsation speed according to wind speed changes according to claim 3, characterized in that: The grille blade flapping vibration actuator includes a flapping vibration actuator motor and a rotating disc; the flapping vibration actuator motor is horizontally fixed below the wind tunnel; the rotating disc is vertically arranged, and the center of the rotating disc is fixedly connected to the motor shaft of the flapping vibration actuator motor.

5. The device for automatically adjusting airflow pulsation speed according to wind speed changes according to claim 4, characterized in that: The grille blade flapping amplitude adjustment mechanism includes a flapping amplitude adjustment motor, a gear, a rack, a slider, a guide rail and a force transmission rod; the guide rail is fixedly mounted on the surface of the rotating disc, the guide rail is radially distributed along the rotating disc, one end of the guide rail is located at the center of the rotating disc, and the other end of the guide rail is located at the edge of the rotating disc; the slider is mounted on the guide rail, and the slider has only linear movement freedom relative to the guide rail; the flapping amplitude adjustment motor is fixedly mounted on the slider, and the motor shaft of the flapping amplitude adjustment motor is distributed perpendicular to the guide rail; one end of the force transmission rod is hinged to the housing of the flapping amplitude adjustment motor, and the other end of the force transmission rod is hinged to the bottom end of the transmission connecting rod; the rack is fixedly mounted on the surface of the rotating disc, and the rack is distributed parallel to the guide rail; the gear is coaxially fixed on the motor shaft of the flapping amplitude adjustment motor, and the gear is meshed with the rack.

6. A method for automatically adjusting airflow pulsation speed according to wind speed changes, using the device for automatically adjusting airflow pulsation speed according to wind speed changes according to claim 5, characterized in that: The steps include: Step 1: Set the flapping amplitude of the grille blades. First, start the flapping vibration actuator motor to drive the rotating disc to rotate until the guide rail is in a vertical state and located on the upper half of the rotating disc; Step 2: Start the flapping wing amplitude adjustment motor to drive the gear to rotate. The gear's rotary motion will be synchronously converted into rolling motion along the rack, thereby driving the flapping wing amplitude adjustment motor and the slider to move linearly along the guide rail until the transmission link is driven upward by half the flapping wing amplitude through the force transmission rod. At this time, the grille blades will deflect around their hinge point with the lifting slide rail, causing the grille blades to change from a horizontal state to a downward deflection state; Step 3: Start the righting motor to drive the screw to rotate. The rotary motion of the screw will be synchronously converted into the linear motion of the nut. The nut will drive the force transmission plate to move downward synchronously, and then drive the lifting movable slide rail to move upward along the guide static slide rail. At the same time, it drives the grille blade to deflect around the hinge point with the transmission connecting rod until the grille blade returns to the horizontal state from the downward deflection state. Step 4: Select a test point in the center of the wind tunnel test section and install a hot wire probe at the selected test point. The distance between the test point and the grille blade should be no less than 10 times the chord length of the grille blade. Step 5: Start the wind tunnel and adjust the wind speed to the set value. Then, the hot wire probe at the test point measures the airflow pulsation velocity in real time. The measured airflow pulsation velocity is then converted into airflow turbulence. Step 6: Start the flapping vibration actuator motor to drive the rotating disc to rotate. The rotating disc drives the transmission connecting rod to make up and down reciprocating motion through the force transmission rod, thereby driving the grille blades to make flapping motion around the hinge point between them and the lifting slide rail; Step 7: Changing the speed of the flapping vibration actuator motor to adjust the flapping vibration frequency of the grille blades to change the airflow pulsation speed, thereby changing the airflow turbulence until the measured airflow turbulence is consistent with the set target turbulence; Step 8: Repeat steps 1 to 7, except that the wind speed setting value remains unchanged, and the flapping amplitude setting value of the grille blades and the target turbulence setting value are changed; Step 9: Repeat steps 1 to 8, but adjust the wind speed setting value. Step 10: Establish a database of wind speed, grille blade flapping amplitude, grille blade flapping vibration frequency, and target turbulence; Step 11: When conducting a wind tunnel test, input the target turbulence. According to the change in wind speed, the corresponding grille blade flapping amplitude and grille blade flapping vibration frequency are automatically matched from the database, so that the airflow turbulence in the wind tunnel is automatically adjusted to the target value.

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