High-lift airfoil with trailing edge microstructure and passive flow control method

Abstract

The application relates to the technical field of airfoil flow control, and provides a high-lift airfoil with a trailing edge microstructure and a passive flow control method. The high-lift airfoil with the trailing edge microstructure comprises a high-lift airfoil body and a trailing edge surface microstructure array. The high-lift airfoil with the trailing edge microstructure can induce small-scale vortexes at the trailing edge by arranging a quasi-spherical convex array on the upper surface trailing edge area, can enhance the momentum exchange inside and outside the boundary layer, can reduce the range of the low-speed separation area of the trailing edge, can inhibit large-scale flow separation, can improve the lift coefficient near the stall angle of attack, can reduce the drag coefficient, and can achieve the purpose of improving the aerodynamic characteristics of the high-lift airfoil near the stall angle of attack. In addition, the application also provides a passive flow control method applied to the high-lift airfoil with the trailing edge microstructure.

Description

Technical Field

[0001] This application relates to the technical field of airfoil flow control, and in particular to a high-lift airfoil with trailing edge microstructure and a passive flow control method. Background Technology

[0002] High-lift airfoils are valuable in applications such as racing car front wings, where maximum downforce is required. These airfoils can generate a large lift coefficient, thus meeting the downforce demands at high speeds. However, high-lift airfoils inherently have a narrow effective angle-of-attack range. When the angle of attack reaches or exceeds a certain critical value, large-scale flow separation occurs on the upper surface of the airfoil, leading to a sharp drop in lift, a significant increase in drag, and a rapid deterioration in aerodynamic performance.

[0003] To suppress flow separation on airfoil surfaces, a passive flow control method has been proposed in the prior art, which involves arranging surface microstructures in the trailing edge region of the airfoil. This method creates local geometric topography on the airfoil surface, using microstructures to disturb the flow field and delay or reduce the formation of the flow separation zone. Compared with active control methods that require external energy input, this passive method achieves control solely by changing the airfoil topography, offering advantages such as simple structure and ease of implementation. Currently, this technology has been applied to some benchmark airfoils. Its basic idea is to create certain protrusions or depressions near the trailing edge to improve the aerodynamic performance of the airfoil at high angles of attack.

[0004] However, the aforementioned trailing edge surface microstructure methods have not been systematically studied when applied to special airfoils with high lift and high camber characteristics. Existing technologies lack parameter adaptation schemes for this type of airfoil in three-dimensional flow environments, and the actual control effect and physical mechanism of microstructures on the stall characteristics of this type of airfoil are not clearly defined. Furthermore, the microstructure forms used in existing studies are relatively singular, failing to fully explore the influence of different geometries and arrangements on the aerodynamic performance of high-lift airfoils. Therefore, how to provide a trailing edge microstructure scheme that can effectively improve the stall characteristics of high-lift, high-camber airfoils remains a pressing technical problem that needs to be solved. Summary of the Invention

[0005] In view of this, this application aims to propose a high-lift airfoil with trailing edge microstructure and a passive flow control method to solve the above-mentioned technical problems.

[0006] To achieve the above objectives, the technical solution of this application is implemented as follows: Firstly, this application proposes a high-lift airfoil with trailing edge microstructures, including: High-lift airfoil body; An array of microstructures on the trailing edge surface is disposed on the upper surface trailing edge region of the high-lift airfoil body to passively control flow and improve the aerodynamic characteristics of the high-lift airfoil near the stall angle of attack.

[0007] Furthermore, the trailing edge surface microstructure array includes one or more rows of quasi-spherical protrusions arranged along the chord and spanwise directions of the high-lift airfoil.

[0008] Furthermore, the chordal position of the arrangement area of ​​the quasi-spherical protrusion is from x / c=0.85 to x / c=1.0.

[0009] Furthermore, the quasi-spherical protrusion has a height of 0.8 mm, a diameter of 3 mm, and a chordal-to-spreading distance of 2.6533 mm.

[0010] Furthermore, the microstructure array on the trailing edge surface includes triangular protrusions, wedge-shaped protrusions, or recessed structures.

[0011] Secondly, this application proposes a passive flow control method for the aforementioned high-lift airfoil with trailing edge microstructure, comprising the following steps: Step 1: Construct the baseline 3D model and the 3D model with trailing edge microstructure of the high-lift airfoil; Step 2: Perform three-dimensional flow field simulation under the same conditions on the reference model and the three-dimensional model with trailing edge microstructure; Step 3: Compare the simulation results to evaluate the control effect of the trailing edge microstructure on the stall characteristics of the high-lift airfoil.

[0012] Furthermore, step 1 specifically includes: Acquire the high-lift airfoil profile data and establish its three-dimensional finite-span airfoil geometric model as a baseline model; Several quasi-spherical protrusions (201) are created in the trailing edge region of the upper surface of the reference model to form a three-dimensional airfoil model with trailing edge microstructure.

[0013] Furthermore, the three-dimensional flow field simulation in step 2 includes the following settings: Computational domain: Construct a three-dimensional semi-circular and semi-rectangular computational domain; Mesh strategy: A structured hexahedral mesh is used, and the mesh is generated based on an O-type mesh topology strategy; Basic assumptions about flow: Air is an incompressible fluid and the flow state is steady-state flow; Solver type: A pressure-based steady-state solver is used, and the SSTk-ω turbulence model is selected. Boundary conditions: The inlet is set as a velocity inlet, the outlet is set as an absolute pressure of 101325 Pa, the surface of the high-lift airfoil is set as a no-slip wall, and the spanwise end face is set as a symmetry plane.

[0014] Furthermore, step 3 specifically includes: Quantitatively compare the differences in lift coefficient, drag coefficient, and lift-to-drag ratio between the baseline model and the three-dimensional model with trailing edge microstructure at the same stall angle of attack. The physical mechanisms by which the trailing edge microstructure induces small-scale vortices, enhances boundary layer momentum exchange, and suppresses large-scale separation are analyzed using flow field visualization techniques.

[0015] Furthermore, the quasi-spherical protrusion (201) created in step 1 specifically includes: Adjusting the geometric parameters of the quasi-spherical protrusions (201) includes adjusting the height to 10%~50% of the local boundary layer thickness, adjusting the diameter and spacing, and changing the regular array arrangement to a non-uniform spacing or staggered arrangement, and / or, Replace the quasi-spherical protrusion (201) with a triangular protrusion, a wedge-shaped protrusion, or a recessed structure, and / or, A wavy leading edge is provided at the leading edge of the high-lift airfoil, or a vortex generator is provided on the surface of the high-lift airfoil, in order to replace the flow control strategy of providing the quasi-spherical protrusion (201) at the trailing edge.

[0016] Compared with existing technologies, the high-lift airfoil with trailing edge microstructure and passive flow control method proposed in this application have the following advantages: (1) This application achieves the following effects by setting a trailing edge surface microstructure array in the trailing edge region of the upper surface of the high-lift airfoil body. The array includes one or more rows of quasi-spherical protrusions, which are arranged along the chord and spanwise directions and their arrangement area is limited to the range from 85% of the chord position to the trailing edge. At the same time, specific geometric parameters are set on the quasi-spherical protrusions. This achieves the effects of inducing small-scale vortices near the stall angle of attack, enhancing momentum exchange between the inside and outside of the boundary layer, reducing the range of the low-speed separation zone at the trailing edge, and suppressing large-scale flow separation. This improves the aerodynamic characteristics of the high-lift airfoil near the stall angle of attack, increases the lift coefficient, and reduces the drag coefficient. In addition, by setting the trailing edge surface microstructure array as triangular protrusions, wedge protrusions, or concave structures, effective flow disturbance is also achieved.

[0017] (2) This application constructs a reference three-dimensional model of a high-lift airfoil and a three-dimensional model with trailing edge microstructures, and performs three-dimensional flow field simulation on both under the same conditions. The three-dimensional semi-circular and semi-rectangular computational domain, the structured hexahedral mesh based on the O-type mesh topology strategy, the air is an incompressible steady-state flow, the pressure-based steady-state solver uses the SST k-ω turbulence model, the inlet is a velocity inlet and the outlet is an absolute pressure, and the airfoil surface is a no-slip wall with the spanwise end face being a symmetric plane, thus achieving an accurate assessment of the stall characteristics of the high-lift airfoil. Furthermore, by quantitatively comparing the differences in lift coefficient, drag coefficient and lift-to-drag ratio at the same stall angle of attack, and by combining flow field visualization methods to analyze the physical mechanism of microstructure-induced small-scale vortices, the effectiveness of trailing edge microstructures in increasing lift and reducing drag and suppressing large-scale separation near the stall point is verified.

[0018] (3) This application provides a variety of alternative implementation methods, including adjusting the geometric parameters of the quasi-spherical protrusions so that their height is 10% to 50% of the local boundary layer thickness and changing the regular array arrangement to a non-uniform spacing or staggered arrangement, or replacing the quasi-spherical protrusions with triangular protrusions, wedge protrusions or concave structures, or setting a wavy leading edge on the leading edge of the high-lift airfoil and setting a vortex generator on the surface, thereby achieving the effect of flexibly selecting flow control strategies in different application scenarios and providing diversified technical solutions for improving the stall characteristics of high-lift, high-camber airfoils. Attached Figure Description

[0019] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a schematic diagram of the high-lift airfoil with trailing edge microstructure described in the embodiments of this application; Figure 2 This is a flow diagram of the trailing edge surface pressure in an embodiment of this application at an angle of attack of 12 degrees; Figure 3 The trailing edge surface pressure streamline diagram of the reference airfoil at an angle of attack of 12 degrees; Figure 4 This is a surface velocity contour plot of an embodiment of this application at an angle of attack of 12 degrees; Figure 5 The surface velocity contour plot is for the reference airfoil at an angle of attack of 12 degrees.

[0020] Explanation of reference numerals in the attached figures: 1. High-lift airfoil body; 2. Microstructure array on trailing edge surface; 201. Quasi-spherical protrusion. Detailed Implementation

[0021] To make the technical solution and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0022] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0023] Furthermore, it should be noted that in the description of this application, if terms such as "upper," "lower," "inner," or "outer" appear, indicating orientation or positional relationship, these are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this application 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 on this application. In addition, if terms such as "first" or "second" appear, they are also used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0024] Furthermore, in the description of this application, unless otherwise expressly defined, the terms "installation," "connection," "joining," and "connector" 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 between two components. Those skilled in the art can understand the specific meaning of the above terms in this application in light of the specific circumstances.

[0025] In this application, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0026] The present application will now be described in detail through exemplary embodiments. However, it should be understood that, without further description, elements, structures, and features in one embodiment may be advantageously incorporated into other embodiments.

[0027] This application relates to the field of airfoil aerodynamic flow control technology, specifically to a high-lift airfoil with trailing edge microstructures and its flow control method. (See reference...) Figure 1The high-lift airfoil with trailing edge microstructures comprises a high-lift airfoil body 1 and a trailing edge surface microstructure array 2. The high-lift airfoil body 1 is a three-dimensional finite-span airfoil section with a specific high-lift airfoil profile. Its profile conforms to aerodynamic design requirements and can generate the required lift within a predetermined angle of attack, serving as the basic structure for bearing aerodynamic loads. The trailing edge surface microstructure array 2 is located on the trailing edge region of the upper surface of the high-lift airfoil body 1, used for passive flow control and improving the aerodynamic characteristics of the high-lift airfoil near the stall angle of attack. The trailing edge surface microstructure array 2 covers the rear region of the upper surface of the high-lift airfoil body 1 and is manufactured using a one-piece molding process with the high-lift airfoil body 1, ensuring structural integrity and a smooth surface transition, avoiding additional flow drag caused by splicing.

[0028] Based on the objective of improving the stall characteristics of high-lift airfoils, in this embodiment, the trailing edge surface microstructure array 2 includes one or more rows of quasi-spherical protrusions 201, which are arranged along the chord and spanwise directions of the high-lift airfoil. The quasi-spherical protrusions 201 are smooth, approximately spherical protrusions with their bottoms smoothly connected to the upper surface of the high-lift airfoil body 1. The protrusion surfaces have no sharp edges, reducing unnecessary flow disturbances. The multiple rows of quasi-spherical protrusions 201 form a regular grid-like arrangement in the chord and spanwise directions, ensuring a uniform distribution of flow disturbances in the trailing edge region and guaranteeing consistent flow control performance across the entire spanwise range.

[0029] To enable the trailing edge surface microstructure array 2 to directly act on the initiation region of flow separation, the chordal position of the quasi-spherical protrusions 201 in this embodiment is from x / c=0.85 to x / c=1.0. When a high-lift airfoil approaches its stall angle of attack, flow separation on the upper surface first develops in the trailing edge region. The region from x / c=0.85 to x / c=1.0 is where the boundary layer momentum depletion is most severe, and it is also the initial location for the formation of large-scale separation vortices. Arranging the quasi-spherical protrusions 201 in this region can disturb the boundary layer before the separation vortices have fully developed, effectively suppressing the further expansion of large-scale separation.

[0030] To achieve optimal flow control without significantly increasing drag, the quasi-spherical protrusion 201 in this embodiment has a height of 0.8 mm, a diameter of 3 mm, and a chordal and spanwise spacing of 2.6533 mm. The height of the quasi-spherical protrusion 201 is taken as 10% to 50% of the local boundary layer thickness. In this embodiment, under the condition of an incoming flow velocity of 20 m / s, the local boundary layer thickness in the trailing edge region of the upper surface of the high-lift airfoil is approximately 1.6 mm to 8 mm. The height of 0.8 mm can just penetrate the bottom region of the boundary layer, inducing small-scale vortices, while avoiding a significant increase in additional pressure drag due to excessive height. The 3 mm diameter and the 2.6533 mm chordal and spanwise spacing are matched to ensure that the vortices induced by adjacent quasi-spherical protrusions 201 produce a synergistic effect, avoiding vortex cancellation, and preventing discontinuous flow disturbances due to excessive spacing, which would prevent the formation of effective boundary layer momentum exchange.

[0031] Based on the requirements of different application scenarios and processing techniques, the trailing edge surface microstructure array 2 includes triangular protrusions, wedge protrusions, or recessed structures. Triangular protrusions are elongated protrusions with a triangular cross-section, which can extend continuously along the spanwise direction or be arranged in segments along the chordwise direction. Their sharp, upstream edges can more efficiently cut the boundary layer, generating stronger small-scale vortices. Wedge protrusions are wedge-shaped protrusions with an inclined plane upstream surface, capable of introducing more high-energy fluid into the boundary layer and enhancing momentum exchange. Recessed structures are spherical or square recesses formed on the upper surface of the airfoil, which can also enhance boundary layer momentum exchange by generating reverse vortex structures. All of the above structures can achieve similar flow control effects to the quasi-spherical protrusion 201, and can be selected according to the actual processing difficulty and aerodynamic performance requirements.

[0032] To accurately evaluate the aerodynamic performance of a high-lift airfoil with a trailing edge microstructure, this application also provides a passive flow control method based on the aforementioned high-lift airfoil with a trailing edge microstructure. This method includes the following steps: Step 1, constructing a baseline 3D model of the high-lift airfoil and a 3D model with the trailing edge microstructure. Step 2, performing 3D flow field simulations under the same conditions on the baseline model and the 3D model with the trailing edge microstructure. Step 3, comparing the simulation results to evaluate the control effect of the trailing edge microstructure on the stall characteristics of the high-lift airfoil. This method uses numerical simulation, which can comprehensively acquire aerodynamic performance data and flow field characteristics of the airfoil at different angles of attack within a relatively low development cost and short cycle, providing a basis for parameter optimization of the trailing edge microstructure.

[0033] To ensure the accuracy and comparability of the model, step 1 specifically includes acquiring the high-lift airfoil profile data and establishing its three-dimensional finite-span airfoil geometric model as a reference model. Several quasi-spherical protrusions 201 are created on the trailing edge region of the upper surface of the reference model to form a three-dimensional airfoil model with trailing edge microstructures. The high-lift airfoil profile data can be obtained by querying a professional airfoil database or by measuring existing airfoils through wind tunnel testing. The span of the three-dimensional finite-span airfoil is determined according to actual application requirements; in this embodiment, the span is twice the airfoil chord length, which can better simulate the three-dimensional flow effect of the finite-span airfoil. When creating the quasi-spherical protrusions 201, the Boolean operation function in the three-dimensional modeling software is used to merge the protrusion structure with the reference airfoil model, ensuring the geometric continuity and surface smoothness of the model and avoiding errors in the simulation results due to model defects.

[0034] To ensure the accuracy and reliability of the 3D flow field simulation results, step 2 includes the following settings: First, a 3D semi-circular and semi-rectangular computational domain is constructed. The radius of the semicircle is 10 times the airfoil chord length, the side length of the semi-rectangle is 15 times the airfoil chord length, the normal direction is 10 times the airfoil chord length both above and below, and the span corresponds to the actual airfoil span. This computational domain size ensures that the airfoil wake develops fully within the domain, avoids interference from the exit boundary on the flow field near the airfoil, and ensures that the simulation results accurately reflect the actual flow state of the airfoil.

[0035] A structured hexahedral mesh was used, generated based on an O-type mesh topology strategy. The normal vectors on the airfoil surface adopted an exponential growth distribution. The height of the first mesh layer was determined to be 0.0139592 mm based on the incoming flow conditions to ensure accurate analytical representation of the near-wall flow and accurately capture velocity gradient changes within the boundary layer. The generated mesh underwent quality checks; the mass values ​​of all mesh elements were distributed between 0.4 and 1.0, exhibiting excellent orthogonality and no negative volume elements, meeting the requirements for high-precision computational fluid dynamics simulations. The basic flow assumptions were that air is an incompressible fluid and the flow state is steady-state.

[0036] A pressure-based steady-state solver is employed, and the SST k-ω turbulence model is selected. This model can accurately simulate both viscous flow near the wall and turbulent flow in the far field, making it suitable for simulation calculations of flow around airfoils. The energy equation is activated to maintain the closure of the equation set in conjunction with the pressure-based coupled solver.

[0037] The fluid material is air, with its density set as an ideal gas. The dynamic viscosity is calculated using the Sutherland formula, accurately simulating the physical properties of air under different temperatures and pressures. The operating pressure is set to 0 Pa, and the ambient reference pressure is standard atmospheric pressure (101325 Pa). Boundary conditions are set as follows: the inlet is a velocity inlet with a velocity of 20 m / s, defined by the velocity components in the X and Y directions to simulate different angles of attack. The pressure outlet is set to an absolute pressure of 101325 Pa. The surface of the high-lift airfoil is set as a no-slip wall, conforming to the actual contact conditions between the fluid and the solid wall. The spanwise end face is set as a symmetric plane to simulate the spanwise flow characteristics of a finite-span airfoil, reducing computational load while ensuring the accuracy of the simulation results. The pressure-velocity coupling uses the Coupled algorithm to improve convergence efficiency and accelerate simulation calculations. In the spatial discretization scheme, the pressure term uses a second-order scheme, while the density, momentum, turbulent kinetic energy ratio dissipation rate, and energy all use second-order upwind schemes to ensure the spatial accuracy of the flow field simulation and reduce errors caused by numerical dissipation. Simulations were performed on the baseline model and the 3D model with trailing edge microstructure within the same angle of attack range, including -4 degrees, 8 degrees, 12 degrees and 16 degrees, to comprehensively evaluate the control effect of the trailing edge microstructure at different angles of attack, covering the entire working range from negative angle of attack to deep stall angle of attack.

[0038] To comprehensively evaluate the control effect of trailing edge microstructures and reveal their physical mechanisms, step 3 specifically includes quantitatively comparing the differences between the baseline model and the three-dimensional model with trailing edge microstructures in terms of stall angle of attack, lift coefficient, drag coefficient, and lift-to-drag ratio. The physical mechanism by which trailing edge microstructures induce small-scale vortices to enhance boundary layer momentum exchange and suppress large-scale separation is analyzed using flow field visualization techniques.

[0039] The simulation results are shown in the table below. At an angle of attack of 12 degrees, the lift coefficient of the baseline model is 1.7463, the drag coefficient is 0.075366, and the lift-to-drag ratio is 23.170926. The lift coefficient of the 3D model with trailing edge microstructure is 1.7746, the drag coefficient is 0.073861, and the lift-to-drag ratio is 24.026211. Compared with the baseline model, the lift coefficient increases by approximately 1.6%, the drag coefficient decreases by approximately 2.0%, and the lift-to-drag ratio increases by approximately 3.7%. At an angle of attack of -4 degrees, the lift coefficient of the baseline model is 0.10728, the drag coefficient is 0.072535, and the lift-to-drag ratio is 1.47901. The lift coefficient of the 3D model with trailing edge microstructure is -0.010661, the drag coefficient is 0.081942, and the lift-to-drag ratio is -0.130104. At an angle of attack of 8 degrees, the baseline model has a lift coefficient of 1.6436, a drag coefficient of 0.043038, and a lift-to-drag ratio of 38.189507. The 3D model with trailing edge microstructures has a lift coefficient of 1.6196, a drag coefficient of 0.044464, and a lift-to-drag ratio of 36.424973. At an angle of attack of 16 degrees, the baseline model has a lift coefficient of 1.3534, a drag coefficient of 0.18956, and a lift-to-drag ratio of 7.139692. The 3D model with trailing edge microstructures has a lift coefficient of 1.3712, a drag coefficient of 0.19011, and a lift-to-drag ratio of 7.212666.

[0040]

[0041] The data above indicate that trailing edge microstructures slightly reduce the lift coefficient and lift-to-drag ratio at small angles of attack, representing a minor performance penalty. This is because the microstructures themselves generate some additional drag. At deep stall angles of attack, trailing edge microstructures can still maintain an increase in lift coefficient of approximately 1.3%, although the effect is weaker than at the stall point. This is because at deep stall, flow separation has extended to the entire upper surface, limiting the effective range of the trailing edge microstructures.

[0042] Overall, the control effect of the trailing edge microstructure is closely related to the angle of attack, with the most significant lift-increasing and drag-reducing effects near the stall point. (Refer to...) Figure 2 and Figure 3 Comparing the trailing edge surface pressure streamline diagrams of the embodiment of this application and the reference airfoil at an angle of attack of 12 degrees, it can be seen that the reference airfoil has a large area of ​​recirculation region in the trailing edge region, indicating severe large-scale flow separation. In the embodiment of this application, the range of the recirculation region in the trailing edge region is significantly reduced, and a large number of regular small-scale vortex structures appear, which are uniformly distributed along the spanwise direction. (Refer to...) Figure 4 and Figure 5Comparing the surface velocity cloud maps of the embodiment of this application and the reference airfoil at an angle of attack of 12 degrees, it can be seen that the reference airfoil has a large low-speed region in the trailing edge area, with a large boundary layer thickness, and the low-speed region occupies almost one-third of the rear part of the upper surface. In the embodiment of this application, the range of the low-speed region at the trailing edge is significantly reduced, and the boundary layer thickness is significantly thinner, allowing high-energy fluid to flow more effectively close to the airfoil surface. The above flow field characteristics indicate that the microstructure array 2 on the trailing edge surface induces small-scale vortices through the quasi-spherical protrusions 201. These small-scale vortices can entrain high-energy fluid outside the boundary layer into the interior of the boundary layer, enhancing momentum exchange between the inside and outside of the boundary layer, effectively reducing the range of the low-speed separation region at the trailing edge, thereby suppressing the formation and expansion of large-scale flow separation, and achieving the technical effect of increased lift and reduced drag near the stall point.

[0043] Based on the invention's objective of further optimizing flow control effects and expanding application scope, in this embodiment, the quasi-spherical protrusion 201 created in step 1 specifically includes adjusting the geometric parameters of the quasi-spherical protrusion 201, including adjusting the height to 10% to 50% of the local boundary layer thickness, adjusting the diameter spacing, and changing the regular array arrangement to a non-uniform spacing or staggered arrangement. Alternatively, the quasi-spherical protrusion 201 can be replaced with a triangular protrusion, wedge protrusion, or recessed structure. Alternatively, a wavy leading edge can be provided at the leading edge of a high-lift airfoil, or a vortex generator can be provided on the surface of the high-lift airfoil to replace the flow control strategy of providing the quasi-spherical protrusion 201 at the trailing edge. Adjusting the geometric parameters of the quasi-spherical protrusion 201 can adapt to different Reynolds numbers and angles of attack ranges. For example, at higher Reynolds numbers, the boundary layer thickness is thinner, and the height of the quasi-spherical protrusion 201 can be appropriately reduced to avoid generating excessive additional drag. Non-uniform spacing or staggered arrangement can generate more complex vortex structures, further enhancing the momentum exchange effect of the boundary layer, making it suitable for applications with higher aerodynamic performance requirements. A wavy leading edge, by generating a periodic pressure gradient along the wingspan, induces streamer vortices distributed along the span, which can also replenish momentum to the boundary layer and delay flow separation. Vortex generators, by generating counter-rotating streamer vortices, entrain high-energy fluid from the outside of the boundary layer into the inside; their mechanism is similar to that of trailing edge microstructures, effectively improving the stall characteristics of the airfoil. All of the above alternatives can achieve the invention's objective of improving the stall characteristics of high-lift airfoils, and can be selected based on specific application requirements, engineering conditions, and manufacturing costs.

[0044] The above descriptions are merely some embodiments of this application and are not intended to limit this application. The technical features or structures in the foregoing different embodiments can be arbitrarily combined to form other specific technical solutions as needed. For those skilled in the art, this application can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of the claims of this application.

Claims

1. A high-lift airfoil with trailing edge microstructure, characterized in that, include: High-lift airfoil body (1); The trailing edge surface microstructure array (2) is set in the trailing edge region of the upper surface of the high-lift airfoil body (1) to passively control the flow and improve the aerodynamic characteristics of the high-lift airfoil near the stall angle of attack.

2. The high-lift airfoil with trailing edge microstructure according to claim 1, characterized in that, The trailing edge surface microstructure array (2) includes one or more rows of quasi-spherical protrusions (201) arranged along the chord and span of the high-lift airfoil.

3. The high-lift airfoil with trailing edge microstructure according to claim 2, characterized in that, The chordal position of the arrangement area of ​​the quasi-spherical protrusion (201) is from x / c=0.85 to x / c=1.

0.

4. A high-lift airfoil with trailing edge microstructure according to claim 3, characterized in that, The quasi-spherical protrusion (201) has a height of 0.8 mm, a diameter of 3 mm, and a chordal-to-spreading distance of 2.6533 mm.

5. A high-lift airfoil with trailing edge microstructure according to claim 1, characterized in that, The trailing edge surface microstructure array (2) includes triangular protrusions, wedge protrusions, or recessed structures.

6. A passive flow control method for a high-lift airfoil with trailing edge microstructure according to any one of claims 1 to 5, characterized in that, Includes the following steps: Step 1: Construct the baseline 3D model and the 3D model with trailing edge microstructure of the high-lift airfoil; Step 2: Perform three-dimensional flow field simulation under the same conditions on the reference model and the three-dimensional model with trailing edge microstructure; Step 3: Compare the simulation results to evaluate the control effect of the trailing edge microstructure on the stall characteristics of the high-lift airfoil.

7. The passive flow control method for a high-lift airfoil with trailing edge microstructure according to claim 6, characterized in that, Step 1 specifically includes: Acquire the high-lift airfoil profile data and establish its three-dimensional finite-span airfoil geometric model as a baseline model; Several quasi-spherical protrusions (201) are created in the trailing edge region of the upper surface of the reference model to form a three-dimensional airfoil model with trailing edge microstructure.

8. The passive flow control method for a high-lift airfoil with trailing edge microstructure according to claim 6 or 7, characterized in that, The three-dimensional flow field simulation in step 2 includes the following settings: Computational domain: Construct a three-dimensional semi-circular and semi-rectangular computational domain; Mesh strategy: A structured hexahedral mesh is used, and the mesh is generated based on an O-type mesh topology strategy; Basic assumptions about flow: Air is an incompressible fluid and the flow state is steady-state flow; Solver type: A pressure-based steady-state solver is used, and the SSTk-ω turbulence model is selected. Boundary conditions: The inlet is set as a velocity inlet, the outlet is set as an absolute pressure of 101325 Pa, the surface of the high-lift airfoil is set as a no-slip wall, and the spanwise end face is set as a symmetry plane.

9. The passive flow control method for a high-lift airfoil with trailing edge microstructure according to claim 6, characterized in that, Step 3 specifically includes: Quantitatively compare the differences in lift coefficient, drag coefficient, and lift-to-drag ratio between the baseline model and the three-dimensional model with trailing edge microstructure at the same stall angle of attack. The physical mechanisms by which the trailing edge microstructure induces small-scale vortices, enhances boundary layer momentum exchange, and suppresses large-scale separation are analyzed using flow field visualization techniques.

10. The passive flow control method for a high-lift airfoil with trailing edge microstructure according to claim 6, characterized in that, The quasi-spherical protrusion (201) created in step 1 specifically includes: Adjusting the geometric parameters of the quasi-spherical protrusions (201) includes adjusting the height to 10%~50% of the local boundary layer thickness, adjusting the diameter and spacing, and changing the regular array arrangement to a non-uniform spacing or staggered arrangement, and / or, Replace the quasi-spherical protrusion (201) with a triangular protrusion, a wedge-shaped protrusion, or a recessed structure, and / or, A wavy leading edge is provided at the leading edge of the high-lift airfoil, or a vortex generator is provided on the surface of the high-lift airfoil, in order to replace the flow control strategy of providing the quasi-spherical protrusion (201) at the trailing edge.

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