An active control wind tunnel for separately simulating mean wind and fluctuating wind

Abstract

The present invention discloses an active control wind tunnel for separately simulating mean wind and pulsating wind, belonging to the technical field of wind tunnel experimental research. This wind tunnel is a single test section direct current unsteady wind tunnel. A power section A is arranged at the front section of the wind tunnel. The power section A includes an array of fans for generating pulsating wind located at the very front end of the wind tunnel and a fan A for generating mean wind located in the flow direction of the pulsating wind air flow. The air flows generated by the array of fans and the fan A pass through the test section and are finally discharged from the air outlet at the end of the wind tunnel. A rainfall device is arranged in the test section. The wind tunnel is controlled by two independent active control modules, namely the fan A control system and the array of fans control system. The array of fans and the fan A can be used separately or in combination to achieve the simulation of complex wind field changes. A steady wind tunnel can also be arranged under the unsteady wind tunnel. The two layers of wind tunnels can be used separately or in combination to achieve specific functions such as simulating natural phenomena.

Description

Technical Field

[0001] The present invention relates to the technical field of wind tunnel experimental research, and in particular to an actively controlled wind tunnel for separately simulating mean wind and pulsating wind. Background Art

[0002] A wind tunnel is an experimental device used to simulate the airflow conditions in the atmosphere to study the movement and aerodynamic performance of objects in the air. A wind tunnel usually consists of a wind tunnel, a fan, measuring equipment, and a control system, and is widely used in aerodynamic research in fields such as architecture, aerospace, and automotive. As an important aerodynamic experimental device, a wind tunnel plays an important role in engineering design and research.

[0003] An unsteady wind tunnel can simulate pulsating wind and can provide information on the dynamic response and wind load of a structure in a complex wind field environment. By measuring the dynamic response of the structure in these unsteady wind fields, the vibration characteristics and critical wind speed of the structure can be evaluated, thereby determining the stability and safety of the structure. Unsteady wind tunnel experiments can obtain the aerodynamic characteristics of the structure, including aerodynamic force coefficients, lift and drag characteristics, etc. This information is crucial for optimizing the aerodynamic shape of the structure and improving the performance of the structure. Through experimental data, aerodynamic problems that may exist in the structure, such as aerodynamic instability and vibration, can be identified and solved.

[0004] Currently, unsteady wind tunnels widely use an array of fans as the main driving device. These fans not only need to generate a uniform basic airflow but also need to additionally generate a pulsating wind field that meets the experimental requirements. However, in the prior art, there are many limitations when the fan array combines these two functions. On the one hand, the fan array needs to generate a uniform flow through complex coordinated control, which poses extremely high requirements for the design, operation, and maintenance of the wind tunnel; on the other hand, when generating pulsating wind, its response time is long, and its dynamic adjustment ability is limited, making it difficult to quickly achieve a pulsating wind field with a high frequency. In addition, due to the mechanical and electrical characteristics limitations of the fans, the pulsating wind frequency that can be achieved by the current unsteady wind tunnels is relatively low, making it difficult to meet the needs of some high-frequency unsteady flow experiments. Therefore, it has become an urgent need to develop an unsteady wind tunnel system with a faster response speed and a wider frequency coverage range. Summary of the Invention

[0005] To solve the limitations of traditional unsteady wind tunnels in terms of fast response and high-frequency simulation, the present invention provides an actively controlled wind tunnel for separately simulating mean wind and pulsating wind. Through an independent active control system, precise generation of fast-response mean wind and high-frequency pulsating wind can be achieved, and the wind field parameters can be flexibly adjusted according to the experimental design requirements to provide a variety of complex wind load simulations.

[0006] The active control wind tunnel for separately simulating mean wind and pulsating wind provided by the present invention is a single-test-section direct-current unsteady wind tunnel. A power section A is arranged at the front section of the wind tunnel. The power section A includes an array of fans for generating pulsating wind located at the very front end of the wind tunnel and a fan A for generating mean wind located in the flowing direction of the pulsating wind air current. A direct-current section is arranged between the array of fans and the fan A. The air currents generated by the array of fans and the fan A pass through the test section and are finally discharged from the air outlet at the end of the wind tunnel; a rainfall device is arranged in the test section, and the rainfall device is located directly above the placement position of the building model. A transparent window is also arranged on the test section for observing the experimental phenomena in the wind tunnel.

[0007] The unsteady wind tunnel is controlled by two independent active control modules, namely the fan A control system and the array of fans control system; the fan A control system adopts a system structure of frequency converter + PLC + upper monitoring computer, forms a network topology based on PROFINET (industrial Ethernet), realizes networked digital information transmission and process control, enhances the anti-interference ability, ensures the motor (fan) speed control accuracy, and generates a mean wind inflow that meets the requirements of the flow field index. The array of fans control system adopts a system structure of AC servo driver + AC servo motor + upper PXI (including a control computer), and can output control strategies (instructions) to each servo driver according to the input control logic (mathematical model), so as to actively control the rotation speeds of the small fans in the array, achieve a relatively accurate simulation of complex wind field changes, and actively control the generation of pulsating wind that meets the special flow field characteristic index according to the formulated control logic (mathematical model).

[0008] The array of fans and the fan A can be used separately or in combination to simulate complex wind field changes.

[0009] A steady wind tunnel can also be arranged below the unsteady wind tunnel, and the steady wind tunnel is closely arranged next to the unsteady wind tunnel to form a double-layer wind tunnel structure. The steady wind tunnel is a sealed annular structure with an annular air duct. A power section B is arranged in the annular air duct. A fan B is arranged in the power section B. The mean wind generated by the fan B sequentially passes through the first corner, the large diffusion section, the second corner to reach the first test section, the first test section passes through the third corner and the fourth corner to reach the second test section, and the second test section returns to the power section B through the small diffusion section. The power drive of the fan B adopts an AC variable-frequency speed regulation drive mode. The first test section and the second test section are used to realize mean wind simulation. The first test section is located directly below the unsteady wind tunnel, and an interaction window is arranged between the two to realize the up-and-down connection of the unsteady wind tunnel and the steady wind tunnel.

[0010] The position of the interaction window is close to the air outlet. An adjustable baffle is arranged at a position close to the interaction window in the unsteady wind tunnel. The baffle can be selectively installed vertically or horizontally. When the baffle is installed vertically, it plays a guiding role and blocks the air outlet, so that the generated airflow enters the steady wind tunnel downward through the interaction window, realizing the simulation of complex wind fields; when the baffle is installed horizontally, the baffle covers the interaction window, realizing the isolation between the steady wind tunnel and the unsteady wind tunnel, and a building model for experiments is placed on the baffle.

[0011] Preferably, the array fans of the unsteady wind tunnel are composed of 112 fans in 7 rows and 16 columns. Each fan adopts an AC servo drive mode, and the servo motor is independently driven to operate by the multi-channel synchronous output of analog voltage through the PXI system.

[0012] The two-layer wind tunnel composed of the unsteady wind tunnel and the steady wind tunnel of the present invention can be used alone or in combination to achieve specific functions such as simulating natural phenomena.

[0013] The unsteady wind tunnel has spatial inhomogeneity, temporal inhomogeneity, and controllable spectrum, and can realize the separate simulation of mean wind and pulsating wind. The array fans and fan A can be used alone or in combination to realize the simulation of complex wind field changes. The unsteady wind tunnel can generate a pulsating wind field, realizing a high-frequency pulsating wind field, and is used to study the dynamic performance of building structures under separate high-frequency wind-induced vibrations (such as sine waves, random pulsations, and pulsating winds with segmented changes). The unsteady wind tunnel can also generate a pulsating wind field and a mean wind field, which are used to simulate complex flow field characteristics, study the wind-rain coupling effect, local eddy current effect, and wind-induced vibration response.

[0014] When the steady wind tunnel and the unsteady wind tunnel are used in combination, the following simulations can be carried out:

[0015] (1) Downburst (two-dimensional): Passively simulate the ascending section of the tail. The steady wind tunnel and the unsteady wind tunnel are connected up and down. A grid-type deflector is arranged in the steady wind tunnel to make the airflow go upward, and it is used to study the wind load caused by the airflow in the ascending section of the downburst tail on the structure.

[0016] (2) Downburst (two-dimensional): Actively simulate the descending section of the airflow. The experimental sections of the steady wind tunnel and the unsteady wind tunnel are connected up and down. A baffle is arranged in the experimental section of the unsteady wind tunnel to make the airflow enter the experimental section of the steady wind tunnel downward. The fan B in the steady wind tunnel is not turned on, or the wind speed is small, and it is used to study the wind field characteristics of the descending section of the downburst airflow, etc.

[0017] (3) Tornado (two-dimensional): The steady wind tunnel test section and the unsteady wind tunnel test section are vertically connected. The unsteady wind tunnel is equipped with a baffle to make the air flow downward into the steady wind tunnel test section, reversely simulating the lift force of the tornado. The steady wind tunnel simulates the ground wind speed, and the unsteady wind tunnel generates a rotating air flow to simulate the characteristics of the tornado, which is used to study the wind field characteristics of the tornado lift force, etc.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] First, the unsteady wind tunnel of the present invention has high-frequency response ability, and can generate a high-precision pulsating wind field with specific frequency, amplitude and mode (such as sine wave, random wave or piecewise change), which is used to study phenomena such as high-frequency wind-induced vibration, filling the deficiency of the conventional wind tunnel in simulating the high-frequency wind field.

[0020] Second, the unsteady wind tunnel of the present invention can realize the superposition of the mean wind and the pulsating wind, simulating the complex flow field characteristics, including the wind-rain coupling effect, the local eddy current effect, the irregular wind field, etc., and is widely applicable to the research of wind loads and aerodynamic performance in the fields of bridges, super high-rise buildings and aerospace.

[0021] Third, through the test section design of the vertical connection of the unsteady wind tunnel and the steady wind tunnel, combined with the steady wind tunnel simulation and the air flow downward pressure function of the unsteady wind tunnel, the accurate simulation of the two-dimensional tornado lift characteristics, downburst characteristics and their wind load effects on the structure can be realized, which is applicable to the simulation of natural disaster research and disaster prevention and mitigation design.

[0022] Other advantages, objectives and features of the present invention will be partially reflected by the following description, and partially will be understood by those skilled in the art through the research and practice of the present invention. Brief Description of the Drawings

[0023] Figure 1 It is a schematic diagram of the unsteady wind tunnel structure.

[0024] Figure 2 It is a schematic diagram of the control scheme of the control systems of fan A and fan B.

[0025] Figure 3 It is a schematic diagram of the control scheme of the array fan control system.

[0026] Figure 4 It is a schematic diagram of the combination of the steady wind tunnel and the unsteady wind tunnel.

[0027] Figure 5 It is a schematic diagram of the cross-sectional layout of the steady wind tunnel and the unsteady wind tunnel.

[0028] Figure 6 It is a schematic diagram of the simulation combination of the irregular pulsating wind of the unsteady wind tunnel.

[0029] Figure 7It is a schematic diagram of the coupled simulation of wind and rain in an unsteady wind tunnel.

[0030] Figure 8 It is a schematic diagram of the ascending section at the tail of the passive simulation of a downburst.

[0031] Figure 9 It is a schematic diagram of the descending section of the active simulation of a downburst and the lift of the reverse simulation of a tornado.

[0032] Reference numerals in the figure:

[0033] 1 - Power section A, 2 - Array of fans, 3 - DC section, 4 - Fan A, 5 - Test section, 6 - Air outlet, 7 - Rainfall device, 8 - Transparent window, 9 - Power section B, 10 - First corner, 11 - Large diffusion section, 12 - Second corner, 13 - Large contraction section, 14 - First test section, 15 - Third corner, 16 - Fourth corner, 17 - Second test section, 18 - Small diffusion section, 19 - First turntable, 20 - Building model, 21 - Second turntable, 22 - Unsteady wind tunnel, 23 - Interaction window, 24 - Baffle, 25 - Support, 26 - Flow deflector. Detailed implementation

[0034] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only for the purpose of illustrating and explaining the present invention and are not intended to limit the present invention.

[0035] As Figures 1-9 shown, the active control wind tunnel for separately simulating the mean wind and the fluctuating wind provided by the present invention is a single - test - section DC unsteady wind tunnel 22. A power section A1 is provided at the front section of the wind tunnel 22. The power section A1 includes an array of fans 2 for generating fluctuating wind at the very front end of the wind tunnel and a fan A4 for generating mean wind in the flow direction of the fluctuating wind. A DC section 3 is provided between the array of fans 2 and the fan A4. The airflows generated by the array of fans 2 and the fan A4 pass through the test section 5 and are finally exhausted from the air outlet 6 at the end of the wind tunnel. A rainfall device 7 is provided in the test section 5, and the rainfall device 7 is directly above the placement position of the building model. The structure of the rainfall device 7 is not limited as long as it can perform the function of downward precipitation at the top of the unsteady wind tunnel. At least one transparent window 8 is also provided on the test section 5, which is made of a transparent material and can be used to observe the experimental phenomena inside the wind tunnel from the outside. By adjusting the wind speed and direction of each fan in the array of fans 2, the required fluctuating airflow is generated. The fluctuating wind generated by the array of fans 2 enters the mean - wind area generated by the fan A4 through the straight section 3. The array of fans actively controls the superposition of the fluctuating characteristics to form the superposition of the fluctuating wind and the mean wind, and finally flows out from the air outlet 6.

[0036] The unsteady wind tunnel 22 is controlled by two independent active control modules, namely the fan A1 control system and the array fan 2 control system. By separately controlling the array fan 2 and the fan A4, the pulsating wind and the average wind are separately controlled and simulated. The fan and the array fan can be used alone or in combination to achieve a fast-response and high-frequency simulation of complex wind fields, which is particularly suitable for studying the dynamic responses of engineering facilities such as building structures and bridges to pulsating winds.

[0037] The required pulsating air flow is generated by adjusting the wind speed and direction of each fan in the array fan 2. The rotational speed and direction of each fan in the array can be actively controlled according to the input control logic to achieve a more accurate simulation of complex wind field changes. The maximum wind speed can reach 20 m / s, and the pulsating frequency is as high as 5 Hz. In a specific embodiment, the array fan 2 is composed of a total of 112 fans arranged in 7 rows and 16 columns. Each fan adopts an AC servo drive mode, and the servo motor is independently driven to operate by the multi-channel synchronous output of analog voltage of the PXI system.

[0038] The specific control scheme of the fan A1 control system is as Figure 2 shown. The power drive of the fan A1 adopts an AC variable frequency speed regulation drive mode. According to the input target steady flow information, the upper management computer sends instructions to the DC wind tunnel control system through the Ethernet, and the latter coordinates the operation of each execution unit through the PLC. According to the received instructions, the PLC controls the rotational speed of the 90KW variable frequency motor through the frequency converter, drives the transmission system and the fan system to operate to generate air flow, and at the same time controls the start of the cooling fan to ensure system heat dissipation. The sensor system real-time monitors parameters such as the wind tunnel cavity temperature, the temperature and vibration of the transmission bearing, and the air flow velocity and pressure, and feeds them back to the PLC to achieve closed-loop control, ensuring that the wind tunnel operates under stable and safe conditions and providing a controllable flow field environment for the test.

[0039] The specific control scheme of the array fan 2 control system is as Figure 3 shown. By actively controlling the operation of multiple small servo motors and driving each fan of the array fan to generate unsteady air flow with complex characteristics. The digital intelligent controller adopted for the multi-fan active control includes a model predictive control strategy + a target wind field feedback digital algorithm. First, according to the target wind field input by the computer, the digital intelligent controller predicts the wind field model and transmits it to the PXI system through digital instructions. The PXI controller executes the digital instructions and synchronously outputs various analog instructions for controlling the active fans to the servo driver. The servo motor responds in real time to the driver to provide a power source for each active fan; the feedback digital algorithm forms digital instructions through intelligent calculation by real-time feedback of the wind field data and the target wind field data by the velocity and pressure sensors and temperature sensors distributed at several measurement points in the test section. The PXI controller executes the digital instructions to quickly form an unsteady flow wind field in the wind tunnel.

[0040] AsFigure 4 and 5 As shown in 5 , a steady wind tunnel may also be provided below the unsteady wind tunnel 22. The steady wind tunnel is closely arranged adjacent to the unsteady wind tunnel 22 to form a double-layer wind tunnel structure. The steady wind tunnel is a sealed annular structure with an annular air duct. A power section B9 is arranged in the annular air duct, and a fan B is arranged in the power section B9. The average wind generated by the fan B sequentially passes through a first corner 10, a large diffuser section 11, a second corner 12, and a large contraction section 13 to reach a first test section 14. The first test section 14 passes through a third corner 15 and a fourth corner 16 to reach a second test section 17. The second test section 17 returns to the power section B9 through a small diffuser section 18. A first turntable 19 is arranged in the first test section 14, and a building model 20 for experiments is placed on the first turntable 19. A second turntable 21 is arranged in the second test section 17. The first test section 14 is a high wind speed test section with a maximum wind speed of 51 m / s. The maximum wind speed of the second test section 17 is 18 m / s. The first test section 14 and the second test section 17 are used to realize the simulation of the average wind. The first test section 14 is located directly below the unsteady wind tunnel 22, and an interaction window 23 is arranged between the two to realize the vertical connection between the unsteady wind tunnel and the steady wind tunnel. The power drive of the fan B adopts an AC variable frequency speed regulation drive mode.

[0041] The position of the interaction window 23 is close to the air outlet 6. An adjustable baffle 24 is arranged at a position in the unsteady wind tunnel close to the interaction window. The baffle can be selectively installed vertically or horizontally. When the baffle is installed vertically, it plays a guiding role and blocks the air outlet 6, so that the generated air flow passes downward through the interaction window 23 into the steady wind tunnel to realize the simulation of a complex wind field. When the baffle 24 is installed horizontally, the baffle covers the interaction window 23 to realize the isolation between the steady wind tunnel and the unsteady wind tunnel, and the building model 20 for experiments is placed on the baffle 24. Further, a bracket 25 for installing and fixing the double-layer wind tunnel structure may be arranged below the steady wind tunnel.

[0042] In one embodiment, a flow deflector 26 is arranged in the steady wind tunnel. The flow deflector 26 is located below the interaction window 23, and the air flow in the steady wind tunnel is made to flow upward through the flow deflector 26 to simulate the ascending section of a downburst.

[0043] The control system adopted by the fan B is the same as that of the fan A.

[0044] The two-layer wind tunnel composed of the steady wind tunnel and the unsteady wind tunnel of the present invention can be used alone or in combination to realize specific functions such as simulating natural phenomena. Examples are as follows:

[0045] Such as Figure 6As shown in the figure: The baffle 24 covers the interaction window 23. The unsteady wind tunnel is used alone to simulate high-frequency pulsating wind. This mode aims to study the dynamic effects of high-frequency pulsating wind (such as sine wave, random pulsation, and pulsating wind with segmented changes) on buildings. The unsteady wind tunnel only turns on the array fans. Through a precise control system, pulsating winds with different frequencies and amplitudes are configured to achieve the simulation of pulsating wind in the frequency range of 0.1 Hz to 5 Hz, covering the main frequency distribution of typical pulsating wind fields. The rotation speed of the fans is controlled by a servo driver to simulate the change of the high-frequency pulsating wind field.

[0046] As Figure 7 As shown in the figure: The baffle 24 covers the interaction window 23. The unsteady wind tunnel is used alone, and the pulsating wind field + mean wind field are used in combination; this combination is used to study the coupling effect of wind and rain, local eddy current effect, and wind-induced vibration response. In the unsteady wind tunnel, the fan A provides a stable background wind speed and direction. By adjusting the rotation speed of the fan A, precise control of the target wind speed is achieved; while the array fans simulate the change of the wind field in the real environment through pulsating wind, and quickly generate a pulsating wind field with high frequency, amplitude, and waveform. Thus, a complex flow field of the superposition of pulsating wind and mean wind is simulated. The rainfall device is used to simulate the rainfall load.

[0047] As Figure 8 As shown in the figure, the baffle 24 is installed vertically to achieve the up-and-down connection of the steady wind tunnel and the unsteady wind tunnel; the steady wind tunnel and the unsteady wind tunnel are combined to simulate a downburst (two-dimensional), passively simulate the ascending section of the tail, and mainly study the ascending characteristics of the airflow. Steady wind tunnel part: A grid-type flow deflector 26 is set in the first test section to ensure the upward flow of the airflow. Unsteady wind tunnel part: The pulsating characteristics of the ascending airflow are generated through the control system to simulate the dynamic behavior of the downburst. Sensors can also be set to monitor the airflow speed and direction and feed back to the control system in real time to adjust the wind speed and direction of the unsteady wind tunnel.

[0048] As Figure 9 As shown in the figure, the baffle 24 is installed vertically to achieve the up-and-down connection of the steady wind tunnel and the unsteady wind tunnel; the steady wind tunnel and the unsteady wind tunnel are combined to actively simulate the descending section of the airflow or reversely simulate the lift of a tornado to study the impact of the descending airflow or tornado on buildings. Steady wind tunnel part: The first test section is connected up and down with the unsteady wind tunnel. The fan B in the steady wind tunnel is turned off or set to a low wind speed to reduce the interference of the background wind on the experiment, and cooperate with the rainfall device 7 to simulate the wind and rain load. The steady wind tunnel part in the tornado mode simulates the ground wind speed, and the unsteady wind tunnel part generates a rotating air current through the control system to simulate the characteristics of a tornado. By adjusting the rotation speed and direction of the fans, an air current conforming to the characteristics of a tornado is created.

[0049] The above are only the preferred embodiments of the present invention, and do not impose any form of limitation on the present invention. Although the present invention has been disclosed above with the preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to equivalent embodiments with equivalent changes within the scope of the technical solution of the present invention by using the above-disclosed technical content. However, as long as it does not depart from the content of the technical solution of the present invention, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. An active control wind tunnel for separately simulating mean wind and pulsating wind, characterized in that This wind tunnel is a single-test-section direct-current unsteady wind tunnel. At the front section of the wind tunnel, a power section A is set up. The power section A includes an array of fans at the very front end of the wind tunnel for generating pulsating wind and a fan A for generating mean wind in the flowing direction of the pulsating wind current. A direct-current section is set between the array of fans and the fan A. The airflows generated by the array of fans and the fan A pass through the test section and are finally discharged from the air outlet at the end of the wind tunnel. A rainfall device is set inside the test section, which is directly above the placement position of the building model. This wind tunnel is controlled by two independent active control modules, namely the fan A control system and the array of fans control system. The fan A control system adopts a system structure of a frequency converter, a PLC, and an upper monitoring computer, forming a network topology based on an industrial Ethernet to achieve networked digital information transmission and process control. The array of fans control system adopts a system structure of an AC servo driver, an AC servo motor, and an upper PXI. According to the input control logic, it outputs control strategies to each servo driver, thereby actively controlling the wind speed and direction of each fan in the array and being able to generate the required pulsating airflows. The array of fans and the fan A can be used separately or in combination to simulate complex wind field changes. This active control wind tunnel that separately simulates mean wind and pulsating wind also includes a steady wind tunnel set below the unsteady wind tunnel. The steady wind tunnel is closely set against the unsteady wind tunnel to form a double-layer wind tunnel structure. An interaction window is set between the steady wind tunnel and the unsteady wind tunnel to achieve the up-and-down connection between the unsteady wind tunnel and the steady wind tunnel. The position of the interaction window is close to the air outlet. An adjustable baffle is set at the position in the unsteady wind tunnel close to the interaction window. This baffle can be selectively installed vertically or horizontally. When the baffle is installed vertically, it plays a guiding role and blocks the air outlet, making the generated airflow pass downward through the interaction window into the steady wind tunnel to simulate a complex wind field. When the baffle is installed horizontally, the baffle covers the interaction window to isolate the steady wind tunnel and the unsteady wind tunnel, and a building model for experiments is placed on the baffle.

2. The active control wind tunnel for separately simulating mean wind and pulsating wind according to claim 1, wherein The steady wind tunnel is a sealed annular structure with an annular air duct. A power section B is set inside the annular air duct. A fan B is set inside the power section B. The mean wind generated by the fan B passes through the first corner, a large diffusion section, the second corner in sequence to reach the first test section. The first test section passes through the third corner and the fourth corner to reach the second test section. The second test section returns to the power section B through a small diffusion section. The first test section is directly below the unsteady wind tunnel.

3. The active control wind tunnel for separately simulating mean wind and pulsating wind according to claim 2, wherein The control system of the fan B is the same as that of the fan A control system.

4. The active control wind tunnel for separately simulating mean wind and pulsating wind according to claim 1, wherein A transparent window is also set on the unsteady wind tunnel for observing the experimental phenomena inside the wind tunnel.

5. The active control wind tunnel for separately simulating mean wind and pulsating wind according to claim 2, wherein The power drive of the fan B in the steady wind tunnel adopts an AC variable-frequency speed-regulating drive mode.

6. The active control wind tunnel for separately simulating mean wind and pulsating wind according to claim 1, wherein The array of fans in the unsteady wind tunnel consists of a total of 112 fans arranged in 7 rows and 16 columns. Each fan adopts an AC servo drive mode, and the servo motor is independently driven to operate by the multi-channel synchronous output of analog voltage through the PXI system.

7. The active control wind tunnel for separately simulating mean wind and pulsating wind according to claim 1, characterized in that, When the baffle covers the interaction window, the array fans in the unsteady wind tunnel are used alone to simulate pulsating wind. The array fans and the fan A are used in combination and cooperate with the rainfall device to simulate wind-rain coupling.

8. The active control wind tunnel for separately simulating mean wind and pulsating wind according to claim 1, characterized in that, When simulating the ascending section of a downburst, the baffle in the unsteady wind tunnel is installed vertically to block the air outlet. A deflector is set in the steady wind tunnel, and the deflector is located below the interaction window. The airflow in the steady wind tunnel is made to flow upward through the deflector. The unsteady wind tunnel generates the pulsating characteristics of the upward airflow to simulate the dynamic behavior of the downburst.

9. The active control wind tunnel for separately simulating mean wind and pulsating wind according to claim 2, characterized in that When simulating the descending section of a downburst, the baffle in the unsteady wind tunnel is installed vertically to play a guiding role. The fan B in the steady wind tunnel is turned off or set to a low wind speed, and it cooperates with the rainfall device to simulate wind-rain load. When simulating a tornado, the steady wind tunnel simulates the ground wind speed, and the unsteady wind tunnel generates a rotating airflow to simulate the characteristics of the tornado.

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