Controllable rotational airflow generation system and method thereof

Abstract

The application discloses a controllable rotating airflow generating system and a method thereof, and belongs to the technical field of aerodynamic experiment equipment. The system comprises an annular fan array, a bottom fan array, a fan angle adjusting mechanism and a control system. The annular fan array is arranged around the center of an experimental area and generates a tangential rotating airflow through the angle adjusting mechanism; the bottom fan array is located below the annular area and generates an axial upward airflow. The control system independently adjusts the rotating speed and angle of each fan, realizing the superposition and accurate coupling of the rotating airflow and the upward airflow. The application can generate a stable, controllable and repeatable rotating upward airflow structure, truly simulates extreme wind environments such as tornadoes, and meets the wind resistance test and aerodynamic research requirements of aircrafts such as eVTOL and unmanned aerial vehicles, and has the advantages of flexible structure, high control precision and wide application range.

Description

Technical Field

[0001] This invention belongs to the field of aerodynamic experimental equipment and controllable wind field generation technology, specifically relating to a controllable rotating airflow generation system and method. Background Technology

[0002] In natural meteorological disasters, extreme wind fields such as tornadoes and dust devils exhibit significant three-dimensional flow field characteristics. Their airflow structure includes not only a tangential component rotating at high speed around a central axis, but also strong axial (vertical) updrafts and radial (horizontal) converging airflows. This complex flow field, coupled with rotation and updraft, poses severe challenges to the aerodynamic performance, stability, and control laws of aircraft. However, existing aerodynamic experimental equipment faces significant technical bottlenecks in simulating such flow fields.

[0003] Currently, general-purpose direct-flow or recirculation wind tunnels are primarily designed to generate unidirectional, uniform, and stable airflow, mainly for conventional steady aerodynamic testing. While some specialized wind tunnels are capable of generating rotating airflow, most employ central guide vanes or fixed guide vanes. This method often results in rotating airflow accompanied by significant turbulence, and the rotation intensity and axial wind speed are difficult to adjust independently. Changing the total wind speed alters the rotation intensity, making precise control of the flow field structure impossible.

[0004] Furthermore, existing rotating flow field generation devices typically employ closed-loop pipe structures, limiting the experimental space and preventing the addition of extra axial airflow below the experimental area. This makes it impossible to simulate the vertical circulation structure of a tornado, where air is drawn in from the bottom and expelled from the top. Current technology lacks an experimental device capable of simultaneously and precisely controlling the tangential velocity (rotation), axial velocity (rise), and radial velocity (convergence) of the airflow.

[0005] Therefore, there is an urgent need for a new type of controllable rotating airflow generation system to solve the technical problems of uncontrollable, non-repeatable, undecoupled and unadjustable airflow structure and inability to simulate real three-dimensional extreme wind fields in the existing technologies. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a controllable rotating airflow generation system and method to address the shortcomings of the prior art, thereby solving the technical problems of existing devices being unable to independently and accurately control the rotation speed and rising speed, unable to flexibly adjust the direction and intensity of the rotating airflow, having uncontrollable and non-repeatable airflow structure, and having limited simulation flexibility and applicability.

[0007] The present invention adopts the following technical solution: A controllable rotating airflow generation system includes an annular fan unit array, a bottom fan array, a fan angle adjustment mechanism, and a control system; The annular fan unit array is formed by arranging multiple fan units in a circular direction to form a ring structure. The annular fan unit array is arranged around the center of the experimental area, and each fan unit is installed on the fan angle adjustment mechanism. The fan angle adjustment mechanism is used to adjust the air outlet direction of the fan unit so that the air outlet has a tangential velocity component, thereby forming a rotating airflow in the experimental area. The bottom fan array is arranged below the area enclosed by the annular fan unit array. The bottom fan array consists of multiple fans, and the air outlet direction of each fan is basically vertically upward to generate an axially rising airflow. The control system is connected to the annular fan unit array and the bottom fan array respectively, and is used to adjust the rotation speed and installation angle of each fan unit in the annular fan unit array and the rotation speed of each fan in the bottom fan array, so that the rotating airflow and the axial rising airflow are superimposed to form a controllable rotating rising airflow structure.

[0008] Preferably, each of the fan units is mounted on a support structure, the support structure including a fan mounting base and a fan angle adjustment mechanism.

[0009] Preferably, the fan angle adjustment mechanism allows the fan unit to rotate about the mounting axis.

[0010] Preferably, the fan angle adjustment mechanism allows the fan unit to rotate about a vertical axis or an inclined axis.

[0011] Preferably, the rotational speed of each fan unit in the annular fan unit array can be adjusted independently.

[0012] Preferably, the wind speed of each fan in the bottom fan array is adjustable, and the multiple fans in the bottom fan array are arranged in a matrix and installed on the bottom support structure of the experimental area.

[0013] Preferably, each fan in the bottom fan array includes a fan body, a motor drive system, and an independent controller.

[0014] Preferably, the installation angle of the fans in the annular fan unit array can be […]. Adjustable within the range of 90° to +90°.

[0015] Preferably, the annular fan unit array is arranged in an approximately annular structure, wherein the approximately annular structure is a polygon, a partial annular structure, or a combination of multiple arc-shaped structures.

[0016] Another technical solution of the present invention is a method for generating controllable rotating airflow, applied to the aforementioned controllable rotating airflow generation system, comprising: By adjusting the installation angle of each fan unit in the annular fan unit array through the control system, the annular fan unit array generates a rotating airflow with a tangential velocity component. By adjusting the rotational speed of the fan units at different positions in the annular fan unit array through the control system, the angular velocity of the rotating airflow becomes a spatial function. , Indicates the radial distance from the center of rotation. Indicates vertical height, controlling the velocity distribution of the rotating airflow; The speed of each fan in the bottom fan array is adjusted by the control system, so that the bottom fan array generates an axial upward airflow. By making the fan speed near the bottom of the experimental area in the annular fan unit array lower than the fan speed near the top of the experimental area, and combining it with the axial upward airflow generated by the bottom fan array, a core region of rotating upward airflow is formed.

[0017] Compared with the prior art, the present invention has at least the following beneficial effects: A controllable rotating airflow generation system decouples the generation of rotating airflow from the generation of axially rising airflow. Traditional systems generate rotation through a tangential component, while the bottom array provides vertical upward buoyancy for simulation. When simulating complex flow fields such as tornadoes, conventional devices often struggle to simultaneously adjust the rotational and upward velocities, leading to a rigid airflow structure. This invention, through a physically separated structural design, allows the control system to independently adjust the tangential force of the ring array and the axial force of the bottom array, significantly expanding the simulation range of the wind field. It can simulate both weak upward and strong rotating airflows, as well as strong upward and weak rotating airflows. Furthermore, the ring arrangement around the center of the experimental area ensures the symmetry and convergence of the airflow, providing a stable and controllable rotating upward airflow core for the experimental area, thus solving the technical problems of uncontrollable and unrepeatable airflow structures in existing technologies.

[0018] Furthermore, the support structure of the fan unit provides the necessary mechanical stability and functional foundation for the system. When the fan operates at high speed, it generates severe vibrations and counter-torque. The robust mounting base effectively suppresses vibration transmission, ensuring the accuracy of experimental data. The load-bearing and adjustment functions are modularly separated. The fan mounting base secures the fan body, while the angle adjustment mechanism changes the airflow direction, making fan maintenance and replacement extremely convenient without disassembling the complex adjustment mechanism. The standardized mounting base design allows for adaptation to different fan unit specifications, improving the system's versatility and scalability, and reducing equipment maintenance costs and upgrade complexity.

[0019] Furthermore, by simply rotating, the angle between the fan outlet and the horizontal plane can be continuously changed, thereby precisely adjusting the ratio of the tangential and radial components of the airflow without changing the fan speed. The structure is simple, the response is rapid, and the positioning is accurate. Compared with adjusting the airflow direction through guide vanes, directly rotating the fan body avoids the wind resistance loss and turbulence interference caused by guide vanes, ensuring the purity and stability of the outlet airflow, and making the generated rotating airflow more in line with the ideal model of fluid mechanics.

[0020] Furthermore, the introduction of tilt axis or vertical axis rotation means that the fan's outlet vector can point in any direction in space, enabling the system to not only generate horizontal tangential rotational force, but also generate converging or diverging airflows pointing towards the center at different heights of the ring array, significantly improving the realism and accuracy of the simulation.

[0021] Furthermore, by independently controlling the rotational speed of each fan, the system can break the symmetry of the ring and simulate rotating airflow with a specific phase difference or intensity gradient. It can also simulate the translational motion of airflow or asymmetric force environment, and can be used to offset the small airflow inhomogeneities in the experimental area. Active flow field correction can be achieved through feedback adjustment.

[0022] Furthermore, the matrix arrangement can effectively eliminate airflow dead zones and provide more uniform bottom lifting force. By adjusting the speed of the bottom fans at different positions, the flatness or concavity of the rising airflow can be controlled. Through the combination of axial control and circumferential tangential control, the system can simulate various extreme working conditions from gentle rising airflow to violently rotating rising airflow, meeting the complex needs of multiple scenarios such as UAV take-off and landing, and aircraft wind resistance testing.

[0023] Furthermore, the bottom fan unit with an integrated independent controller enables plug-and-play intelligent control. Each fan, as an independent intelligent node, can receive instructions from the central control system and provide real-time feedback on its operating status. This not only reduces the burden on the main control system but also improves the system's response speed and reliability. Even if a fan unit fails, the system can compensate for the output of other fans through algorithms, maintaining the continuity of the experiment.

[0024] Furthermore, the coverage range of -90° to +90° means that the fan can blow inward, horizontally, or outward, enabling a single device to simulate a variety of distinct meteorological phenomena. It covers all possible combinations of tangential and radial components, providing a great degree of experimental freedom for studying the influence of airflow angle on rotating structures. This is a key parameter boundary for achieving controllable airflow generation.

[0025] Furthermore, this invention allows the fans to be arranged in polygonal or partially arc-shaped configurations, which enables the system to be flexibly embedded into existing laboratory structures. By controlling the algorithmic compensation of the angle and speed of each fan, high-quality rotating airflow can be generated, reducing the installation threshold of the equipment. It is suitable not only for newly built dedicated wind tunnels but also for the renovation of existing ordinary laboratories.

[0026] A controllable rotating airflow generation method breaks away from the traditional uniform rotation model by setting the bottom fan of the annular array to rotate at a lower speed than the top fan. This constructs an angular momentum distribution that increases with height, simulating the energy accumulation process of a tornado developing upwards from the ground contact point. Combined with the axial lift of the bottom fan, the airflow undergoes strong coupling and entrainment in the core region, forming a visually funnel-shaped airflow structure. This method not only generates airflow but also a specific flow field topology, allowing experimental subjects to withstand aerodynamic tests highly similar to those of a real tornado in a laboratory environment. This provides a unique and effective ground-based simulation method for studying the dynamic response of aircraft in extreme wind fields.

[0027] In summary, this invention achieves independent and precise control and coupling superposition of rotating airflow and axial upward airflow through the coordinated control of annular adjustable angle fan array and bottom fan array. It can generate stable, controllable and repeatable rotating upward airflow, which can realistically simulate extreme wind environments such as tornadoes. It meets the needs of extreme wind environment testing and aerodynamic research for electric vertical take-off and landing aircraft, drones and other aircraft. The device has a flexible structure, high control precision and wide applicability.

[0028] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the following description of the relative embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the system of the present invention.

[0031] Among them: 1. Annular fan unit array; 2. Annular fan unit; 3. Fan angle adjustment mechanism; 4. Bottom fan array. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "one side," "one end," and "one side," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0034] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0035] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0036] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0037] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0038] The accompanying drawings illustrate various structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0039] This invention provides a controllable rotating airflow generation system and method. Through the coordinated control of a ring-shaped adjustable angle fan array and a bottom fan array, the rotating airflow and the axial upward airflow are independently and precisely controlled and coupled and superimposed to generate a stable, controllable, and repeatable rotating upward airflow. It can realistically simulate extreme wind environments such as tornadoes and is suitable for extreme wind environment testing and aerodynamic research of aircraft such as electric vertical take-off and landing aircraft (EVTOL) and drones. It has a flexible structure, high control precision, and wide applicability.

[0040] Please see Figure 1 The present invention discloses a controllable rotating airflow generation system, comprising an annular fan unit array 1, a bottom fan array 4, a fan angle adjustment mechanism 3, and a control system.

[0041] The annular fan unit array 1 consists of multiple annular fan units 2 arranged in a circular direction to form a ring structure, with the array of annular fan units 2 arranged around the center of the experimental area. Each annular fan unit 2 is mounted on a fan angle adjustment mechanism 3, allowing the fan outlet direction to be adjusted, thereby changing the directional component of the airflow. By adjusting the installation angle of the annular fan unit 2, the fan outlet direction is made to have a tangential velocity component, thus forming an airflow rotating around the central axis within the experimental area. Adjusting the fan angle changes the direction and intensity of the rotating airflow. Each annular fan unit 2 is driven by an independent controller, and its rotation speed can be adjusted independently, thereby regulating the airflow velocity generated by each fan. Adjusting the rotation speed of the annular fan unit 2 regulates the distribution of the rotating airflow velocity.

[0042] The bottom fan array 4 is arranged below the area enclosed by the annular fan unit array 1. The bottom fan array 4 consists of multiple fans, each of which discharges air in a basically vertical upward direction to generate an axial upward airflow. Each fan in the bottom fan array 4 is independently controlled by a control system, and its wind speed is adjustable, thereby controlling the intensity of the upward airflow.

[0043] The rotating airflow generated by the annular fan unit array 1 and the rising airflow generated by the bottom fan array 4 are superimposed to form a rotating rising airflow structure in the experimental area.

[0044] Rotating airflow velocity components for:

[0045] in, The rotational speed of the annular fan unit 2 is... The installation angle of the fan.

[0046] Updraft velocity component for:

[0047] in, This refers to the rotational speed of the bottom fan.

[0048] The superposition of rotating airflow and rising airflow forms the total airflow. :

[0049] This creates a controllable rotating upward airflow structure.

[0050] The annular fan unit 2 is mounted on the support structure via a fan angle adjustment mechanism 3. This mechanism allows the fan to rotate around its mounting axis, thereby adjusting the fan's outlet direction. By adjusting the fan's mounting angle, the ratio of the tangential to radial components of the airflow is adjusted, thus controlling the intensity and structure of the rotating airflow. Fan angle adjustment is achieved manually or via an electric actuator.

[0051] The control system adjusts the rotational speed, angle, and bottom fan speed of the annular fan unit. By adjusting the rotational speed and angle of the annular fan unit, the intensity and direction of the rotating airflow are controlled. By adjusting the speed of the bottom fan, the intensity of the rising airflow is controlled. By combining and adjusting these parameters, rotating rising airflows of different intensities and structures are generated.

[0052] In a specific embodiment, the controllable rotating airflow generation system includes multiple fan units arranged in a ring and a bottom fan array located within the ring area. The ring-shaped fan units are evenly arranged along the circumference, and each fan unit is fixed to a bracket by a support structure. The support structure includes a fan mounting base and an angle adjustment mechanism, which allows the fan to rotate about a vertical or tilted axis, thereby changing the fan's airflow direction. The fan mounting angle is... Adjustable within the range of 90° to +90°, thereby changing the proportions of the tangential, radial, and axial components of the airflow at the fan outlet.

[0053] Each annular fan unit 2 includes a fan body, a motor drive system, a fan mounting bracket, a fan angle adjustment mechanism 3, and an independent controller. The independent controller is used to adjust the fan speed, thereby controlling the fan's air outlet speed.

[0054] The bottom fan array 4 includes multiple fan units arranged in a matrix and installed on the bottom support structure of the experimental area. The air outlet direction of each fan is basically vertical and upward. Each fan unit also includes a fan body, a motor drive system, and an independent controller.

[0055] The control system is connected to the annular fan unit 2 and the bottom fan, and is used to control the rotational speed of each annular fan unit 2, the angle of each annular fan unit 2, and the rotational speed of each bottom fan.

[0056] A controllable rotating airflow generation method is applied to the aforementioned controllable rotating airflow generation system. During system operation, the angle of the annular fan unit 2 is adjusted by the control system, causing the annular fan unit 2 to generate airflow with a tangential component, thereby forming a rotating airflow within the experimental area. Simultaneously, an upward airflow is provided to the experimental area by controlling the bottom fan array, thus forming an axial airflow component. The rotating airflow and the axial airflow superimpose to form a rotating upward airflow structure within the experimental area. By adjusting the angle and rotational speed of the annular fan unit 2 and the rotational speed of the bottom fan, the intensity, radius, angular velocity, and axial velocity of the rotating airflow can be adjusted, thereby forming rotating upward airflows of different intensities.

[0057] In the independent speed control implementation of the annular fan unit 2, each fan unit in the annular fan unit 2 array is connected to an independent drive controller, allowing the speed of each fan to be controlled individually, without relying on a uniform speed. By independently controlling the speed of each fan, the annular fan unit 2 array can generate airflows of different speeds at different spatial locations, thereby forming a spatially varying rotating airflow structure. The fan speeds in the bottom region of the annular structure are set to lower values, while the fan speeds in the upper region of the annular structure are set to higher values, thus forming a rotating airflow velocity distribution that varies with height within the experimental area. This creates a gradient distribution of the angular velocity of the rotating airflow along the vertical direction, and the airflow rotation intensity varies with height, more closely resembling the airflow structure of a real tornado.

[0058] In the implementation of the spatial distribution control of tornado intensity, the rotational speed of the fans at different positions in the array of annular fan units 2 is adjusted so that the angular velocity of the rotating airflow becomes a spatial function:

[0059] in, Indicates the radial distance from the center of rotation. Indicates the vertical height.

[0060] By adjusting the fan speed at different height positions, the angular velocity distribution of the rotating airflow along the vertical direction can be controlled. By adjusting the fan speed at different circumferential positions, the asymmetric structure of the rotating airflow can be controlled, generating rotating airflow structures with different rotation intensity distributions.

[0061] In the tornado core structure control implementation, by reducing the rotational speed of the fans near the bottom of the experimental area in the annular fan unit 2 array to be lower than that of the fans near the top of the experimental area, the angular momentum of the airflow increases in the vertical direction. Combined with the axial upward airflow generated by the bottom fan array, a stable rotating upward airflow core region is formed. By adjusting different combinations of fan speeds, the diameter of the rotating airflow core, the angular velocity of the rotating airflow, the stability of the rotating airflow, and the shape of the rotating airflow structure are controlled, thereby achieving the generation of a controllable tornado structure.

[0062] In the implementation of the control system, the control system includes multiple independent fan control modules, each corresponding to a fan unit, used to independently control the fan speed. The control system sets the target speed for each fan based on a preset airflow structure target. The spatial distribution of the target rotating airflow is achieved through independent control.

[0063] In a non-perfectly circular implementation, the wind turbine array can be arranged in an approximately circular structure, including polygonal, partially circular, or combinations of multiple arc-shaped structures.

[0064] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0065] Example 1 The system includes a 24-sided annular fan array 1 consisting of 24 axial flow fans, each fixed by an aluminum alloy support frame. The fan mounting base is designed with a universal joint structure, and a worm gear reducer driven by a stepper motor serves as the fan angle adjustment mechanism 3, achieving a rotation angle accuracy of 0.1°. The bottom fan array 4 consists of a matrix of 25 centrifugal fans arranged vertically on the bottom surface enclosed by the annular array. The control system adopts a host computer + PLC + frequency converter architecture. The host computer runs a flow field simulation algorithm to calculate the target speed and target angle of each fan, and sends it to the lower-level PLC via a 485 bus. The PLC outputs a PWM signal to control the frequency converter to adjust the fan motor.

[0066] Example 2 In this embodiment, the fan angle adjustment mechanism 3 is replaced by a hydraulic swing cylinder structure. For high-power, large-size industrial fans, mechanical transmission structures may face insufficient torque. This embodiment uses a hydraulic system for drive, controlling the swing angle of the hydraulic swing cylinder through a proportional directional valve, thereby driving the fan base to rotate. Although this structure has a slightly slower response speed than a motor, it can provide extremely high driving torque, making it suitable for giant wind tunnels simulating large wind turbines or building wind resistance tests.

[0067] Example 3 This embodiment modifies the installation method of the fans. Instead of a fixed support frame, the annular fan array 1 employs a suspended structure. All fan units are mounted on a rigid annular track beam, which is suspended from a load-bearing beam at the top of the laboratory by multiple steel cables. The fan angle adjustment mechanism 3 uses a servo motor in conjunction with a synchronous belt drive. This connection method eliminates the interference of ground vibration on the experimental model, making it particularly suitable for precision measurement experiments that are extremely sensitive to vibration.

[0068] Example 4 For teaching demonstrations or low-cost applications, this embodiment provides a simplified structure. The number of ring-shaped fan arrays 1 is reduced to 8, and the fan angle adjustment mechanism 3 adopts a manual adjustment and locking mechanism. That is, a dial and locking bolt are provided on the fan base. The angle is manually set and locked before the experiment as needed, and no further adjustment is required during operation. The bottom fan array 4 is simplified to a single high-power fan. Although dynamic adjustment capability is sacrificed, the cost is significantly reduced, and the basic rotating upward airflow phenomenon can still be demonstrated.

[0069] To verify the technical effects of the present invention, the applicant conducted CFD (Computational Fluid Dynamics) simulation and physical prototype testing.

[0070] Experimental data: A prototype consisting of 12 annular fans and 9 bottom fans was built. Under simulated tornado conditions, the rotational speed of the upper annular fans was set to 1500 rpm, the rotational speed of the bottom fans was set to 800 rpm (to form an angular momentum gradient), and the rotational speed of the bottom array was set to 1200 rpm.

[0071] Measurement results: Measurements were taken along the central axis of the experimental area using a three-dimensional ultrasonic anemometer.

[0072] At a height of Z=0.5m, the tangential wind speed reaches 8m / s, and the axial upward wind speed is 2m / s.

[0073] At a height of Z=2.0m, the tangential wind speed decreases to 4m / s, while the axial upward wind speed increases to 6m / s.

[0074] Comparative analysis: Compared with traditional fixed-angle wind tunnels, the airflow generated by this invention exhibits a significant coupling characteristic of reduced rotation and enhanced upward movement in the vertical direction, achieving a fitting degree of over 85% with the flow field data of a real tornado. In drone hovering tests, traditional wind tunnels cannot keep drones in the central region, while the system of this invention successfully achieved dynamic hovering tests of drones in the simulated core area of ​​a tornado by adjusting the bottom wind speed.

[0075] In summary, this invention, a controllable rotating airflow generation system and method, successfully solves the technical challenge of traditional wind tunnels' inability to independently and accurately control rotating and rising airflow through a unique "annular lateral + bottom axial" dual-array decoupling structure combined with independent distributed control technology. The system utilizes an annular fan array to generate tangential rotating airflow through angle adjustment, while a bottom fan array provides vertical rising airflow. These two elements are superimposed and coupled in the experimental area to form a stable and controllable rotating rising airflow structure. Mathematical decoupling and independent control of the airflow velocity field are achieved. Furthermore, through independent frequency conversion adjustment of each fan unit, accurate simulation of asymmetric flow fields and complex spatial function distributions is realized. Experimental verification shows that the system can highly reproduce the hydrodynamic characteristics of extreme wind fields such as tornadoes, with a stable and repeatable airflow structure. This invention is flexible in structure and highly adaptable, providing a high-fidelity experimental platform for aerodynamic performance testing and control law research of electric vertical take-off and landing aircraft, UAVs, etc., under extreme wind environments, and has extremely high engineering application value.

[0076] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A controllable rotating airflow generation system, characterized in that, Includes a ring-shaped fan unit array, a bottom fan array, a fan angle adjustment mechanism, and a control system; The annular fan unit array is formed by arranging multiple fan units in a circular direction to form a ring structure. The annular fan unit array is arranged around the center of the experimental area, and each fan unit is installed on the fan angle adjustment mechanism. The fan angle adjustment mechanism is used to adjust the air outlet direction of the fan unit so that the air outlet has a tangential velocity component, thereby forming a rotating airflow in the experimental area. The bottom fan array is arranged below the area enclosed by the annular fan unit array. The bottom fan array consists of multiple fans, and the air outlet direction of each fan is basically vertically upward to generate an axially rising airflow. The control system is connected to the annular fan unit array and the bottom fan array respectively, and is used to adjust the rotation speed and installation angle of each fan unit in the annular fan unit array and the rotation speed of each fan in the bottom fan array, so that the rotating airflow and the axial rising airflow are superimposed to form a controllable rotating rising airflow structure.

2. The controllable rotating airflow generation system according to claim 1, characterized in that, Each of the fan units is mounted on a support structure, which includes a fan mounting base and a fan angle adjustment mechanism.

3. The controllable rotating airflow generation system according to claim 2, characterized in that, The fan angle adjustment mechanism allows the fan unit to rotate about the mounting shaft.

4. The controllable rotating airflow generation system according to claim 3, characterized in that, The fan angle adjustment mechanism allows the fan unit to rotate about a vertical axis or an inclined axis.

5. The controllable rotating airflow generation system according to claim 1, characterized in that, The rotational speed of each fan unit in the annular fan unit array can be adjusted independently.

6. The controllable rotating airflow generation system according to claim 1, characterized in that, The wind speed of each fan in the bottom fan array is adjustable. The multiple fans in the bottom fan array are arranged in a matrix and installed on the bottom support structure of the experimental area.

7. The controllable rotating airflow generation system according to claim 1, characterized in that, Each fan in the bottom fan array includes a fan body, a motor drive system, and an independent controller.

8. The controllable rotating airflow generation system according to claim 1, characterized in that, The installation angle of the fans in the annular fan unit array can be... Adjustable within the range of 90° to +90°.

9. The controllable rotating airflow generation system according to claim 1, characterized in that, The annular fan unit array is arranged in an approximately annular structure, which can be a polygon, a partial annular structure, or a combination of multiple arc-shaped structures.

10. A method for generating controllable rotating airflow, characterized in that, The controllable rotating airflow generation system according to any one of claims 1 to 9 comprises: By adjusting the installation angle of each fan unit in the annular fan unit array through the control system, the annular fan unit array generates a rotating airflow with a tangential velocity component. By adjusting the rotational speed of the fan units at different positions in the annular fan unit array through the control system, the angular velocity of the rotating airflow becomes a spatial function. , Indicates the radial distance from the center of rotation. Indicates vertical height, controlling the velocity distribution of the rotating airflow; The speed of each fan in the bottom fan array is adjusted by the control system, so that the bottom fan array generates an axial upward airflow. By making the fan speed near the bottom of the experimental area in the annular fan unit array lower than the fan speed near the top of the experimental area, and combining it with the axial upward airflow generated by the bottom fan array, a core region of rotating upward airflow is formed.

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