A collaborative jet wing parameterization modeling method for high-altitude long-endurance unmanned aerial vehicles

Abstract

The application provides a cooperative jet wing parameterized modeling method for high-altitude long-endurance unmanned aerial vehicles, comprising the following steps: generating a three-dimensional cooperative jet wing segment shape with a blowing port and a suction port based on a reference airfoil, wing basic parameters, blowing port and suction port parameters, and completing wing shape parameterized modeling; determining diameter, length and position parameters of a fan section pipeline based on duct fan parameters, and completing fan section pipeline parameterized modeling; under the constraint of the wing shape obtained by modeling, taking the blowing port, the suction port and the fan section pipeline as boundaries, generating blowing pipelines and suction pipelines based on pipeline center lines and cross sections, and completing internal pipeline parameterized modeling. The modeling method constructed by the application solves the problem of insufficient internal pipeline shape representation in current cooperative jet research, and provides technical support for designing a cooperative jet wing with excellent aerodynamic performance.

Description

Technical Field

[0001] This invention belongs to the field of UAV wing design technology, specifically relating to a parametric modeling method for cooperative jet wings of high-altitude long-endurance UAVs. Background Technology

[0002] High-Altitude Long-Endurance (HALE) UAVs are characterized by high-altitude deployment and extremely long loiter time, which places extremely stringent requirements on the aerodynamic performance of the wings. They not only need to have a high lift-to-drag ratio to reduce cruise energy consumption and extend endurance, but also need to have sufficient lift coefficient during takeoff and landing to adapt to limited takeoff and landing site conditions and reduce the thrust requirements of the power system.

[0003] Co-Flow Jet (CFJ) active flow control technology is one of the core solutions for achieving the aforementioned aerodynamic design. This technology was first proposed in 2004 by Professor Cha Gecheng of the University of Miami. Its core principle involves setting leading-edge jet inlets and trailing-edge inlets on the upper surface of the airfoil, forming a closed-loop jet system through an internal power unit. The high-speed jet injects energy into the boundary layer of the airfoil's upper surface, effectively suppressing flow separation at high angles of attack and slowing airflow deceleration. This significantly increases the lift coefficient and reduces the drag coefficient of the airfoil and wing without altering the wing's baseline shape, and significantly increases the stall angle of attack. For high-altitude long-endurance UAVs, co-flow jet flow control can increase the maximum lift coefficient of the airfoil by 1 to 2 times; while meeting the same lift requirements, the wing area can be significantly reduced, even to about half that of a conventional layout, thereby effectively reducing the risk of aeroelastic coupling and structural strength design requirements. Compared to conventional mechanical lift-enhancing devices, the synergistic jet technology does not disrupt the laminar flow characteristics of the airfoil during cruise, perfectly matching the aerodynamic design requirements of high-altitude long-endurance UAVs under all operating conditions, and possesses extremely high engineering application value.

[0004] However, the current collaborative jet technology still faces core technological bottlenecks in its engineering application to the wings of high-altitude long-endurance UAVs, particularly the lack of a set of integrated parametric modeling methods for wing shape and internal ducts that are adapted to engineering aerodynamic design requirements. These bottlenecks are specifically reflected in the following aspects:

[0005] Firstly, existing research on cooperative jet wings mostly focuses on aerodynamic performance simulation and flow mechanism analysis with fixed geometric configurations, resulting in a severe lack of parametric modeling capabilities. Existing modeling schemes can only adjust a few two-dimensional airfoil parameters such as jet nozzle width, jet nozzle position, and jet angle, and cannot achieve full parametric modeling of the wing's three-dimensional shape (including spanwise chord distribution, torsion distribution, wingtip configuration, etc.), jet nozzle spanwise layout, and internal jet channels. Each design iteration requires rebuilding the geometric model, resulting in long design cycles and low iteration efficiency, which cannot support the refined aerodynamic optimization design requirements of cooperative jet wings.

[0006] Secondly, existing modeling methods for cooperative jet wings generally suffer from the problem of "disconnection between internal and external flow fields." Most studies, in order to simplify the calculation process, reduce the cooperative jet effect to ideal boundary conditions such as the velocity inlet of the blow-off port and the pressure outlet of the intake port, completely ignoring the actual flow characteristics of the internal jet channels. This leads to discrepancies between the wing aerodynamic performance obtained from numerical simulations and the actual performance under real jet conditions. It also makes it impossible to accurately assess the impact of parameters such as pressure loss in the internal channels and jet outlet uniformity on wing aerodynamic performance. Ultimately, the final design often results in actual aerodynamic benefits lower than theoretical expectations, failing to meet the accuracy requirements for engineering applications.

[0007] Third, the few collaborative jet wing modeling schemes that consider internal jet channels can only achieve modeling of fixed geometric structures. They cannot achieve parametric control of complex shapes such as the profile, cross-sectional area, and spatial orientation of the internal channels. They cannot adapt to the aerodynamic design requirements of high-altitude long-endurance UAVs in high-altitude low Reynolds number environments, which seriously restricts the engineering application and promotion of collaborative jet technology in the field of high-altitude long-endurance UAVs.

[0008] Therefore, developing a parametric modeling method for cooperative jet wings for high-altitude long-endurance UAVs, and improving the iterative efficiency and simulation accuracy of cooperative jet wing aerodynamic design, has become a core technical problem that urgently needs to be solved in this field. Summary of the Invention

[0009] To address the shortcomings of existing technologies, this invention provides a parametric modeling method for cooperative jet wings of high-altitude long-endurance unmanned aerial vehicles (UAVs), which can effectively solve the aforementioned problems.

[0010] The technical solution adopted in this invention is as follows:

[0011] This invention provides a parametric modeling method for cooperative jet wings of high-altitude long-endurance unmanned aerial vehicles (UAVs), comprising the following steps:

[0012] Step S1: Establish a global coordinate system with the chord direction of the wing as the x-axis, the normal direction as the y-axis, and the spanwise direction as the z-axis; given a reference airfoil, set the basic parameters of the wing, the air inlet parameters, and the air inlet parameters; under the global coordinate system, based on the reference airfoil, the basic parameters of the wing, the air inlet parameters, and the air inlet parameters, generate a three-dimensional cooperative jet wing section shape with air inlets and air inlets, and complete the parametric modeling of the wing shape;

[0013] Step S2: Determine the fan section pipe parameters based on the duct fan parameters to complete the parametric modeling of the fan section pipe.

[0014] Step S3: Under the constraints of the wing shape obtained from the modeling, with the air inlet, air inlet and fan section pipe as the boundary, and based on the pipe centerline control parameters and pipe section parameters, the air inlet pipe and air inlet pipe are generated respectively to complete the parametric modeling of the internal pipes, and then the cooperative jet wing is modeled.

[0015] Furthermore, the specific implementation method of step S1 includes:

[0016] Step S1.1, the basic parameters of the wing include chord length and span; the air inlet parameters include air inlet position parameters and air inlet size parameters; the air intake parameters include air intake position parameters and air intake size parameters;

[0017] Step S1.2: Create an air inlet on the upper surface of the reference airfoil according to the air inlet position parameters and air inlet size parameters; create an air inlet on the upper surface of the reference airfoil according to the air inlet position parameters and air inlet size parameters; the downward direction of the air inlet and the air inlet is along the normal of the airfoil surface.

[0018] Step S1.3: On the upper surface of the reference airfoil, determine and cut off the airfoil profile located between the air inlet and the air inlet; the remaining uncut airfoil profile of the reference airfoil is called the remaining airfoil profile.

[0019] Step S1.4: Shift the cut-off airfoil profile downwards so that the left endpoint of the airfoil profile aligns with the lower endpoint of the air inlet; then rotate the airfoil profile with the left endpoint as the center so that the right side of the airfoil profile passes through the lower endpoint of the air inlet; cut off the portion of the airfoil profile that extends beyond the lower endpoint of the air inlet. At this point, the airfoil profile located between the lower endpoint of the air inlet and the lower endpoint of the air inlet is the target airfoil profile.

[0020] Step S1.5: The target airfoil profile is combined with the remaining airfoil profile of the reference airfoil to form the two-dimensional cooperative jet airfoil;

[0021] Step S1.6: Stretch the two-dimensional cooperative jet airfoil according to the span parameter to obtain the three-dimensional cooperative jet airfoil section shape.

[0022] Furthermore, the air inlet position parameter is the relative position of the air inlet from the leading edge of the airfoil along the x-direction, and the air inlet size parameter is the ratio of the downward length of the air inlet perpendicular to the airfoil surface to the chord length; the air inlet position parameter is the relative position of the air inlet from the leading edge of the airfoil along the x-direction, and the air inlet size parameter is the ratio of the downward length of the air inlet perpendicular to the airfoil surface to the chord length.

[0023] Furthermore, the specific implementation method of step S2 includes:

[0024] Step S2.1: Determine the fan section pipe parameters based on the duct fan parameters; wherein, the duct fan parameters include the duct fan size parameters and position parameters; the fan section pipe parameters include the diameter of the fan section pipe, the coordinates of the starting position center point, and the length of the fan section pipe;

[0025] The specific determination method is as follows: based on the duct fan size parameters and position parameters, determine the diameter of the fan section pipe and the coordinates of the starting center point; combine the duct fan size parameters to determine the diameter and length of the fan section pipe;

[0026] Step S2.2, based on the fan section duct parameters, complete the parametric modeling of the fan section duct, including:

[0027] At the starting position of the fan segment duct, a plane is created perpendicular to the chord line; in the plane, a circular cross-section is drawn with the center point of the starting position as the center and the diameter of the fan segment duct as the diameter; the circular cross-section is stretched to the length of the fan segment duct to generate the fan segment duct; the fan segment duct is a circular duct.

[0028] Furthermore, in step S3, the principle of parametric modeling of the blowing pipe is the same as that of parametric modeling of the suction pipe.

[0029] Furthermore, the method for parametric modeling of the air blowing pipe is as follows:

[0030] Step S3.1: Fix the center point of the air inlet and the center point of the starting position of the fan section pipe, and use the controllable generation algorithm of the air pipe center line to generate the air pipe center line between the center point of the air inlet and the center point of the starting position of the fan section pipe.

[0031] Step S3.2: Select several control nodes on the center line of the air blowing pipe, and generate a control section perpendicular to the center line of the air blowing pipe at each control node, thereby controlling the shape change of the air blowing pipe along the center line of the air blowing pipe.

[0032] Step S3.3: For each control section, a hyperelliptic function is used to generate the cross-sectional profile of the air blowing pipe. The parameters of the hyperelliptic function used for each control section are continuously controlled along the center line of the air blowing pipe to ensure a smooth transition of the air blowing pipe. For the cross-sectional profiles of the air blowing pipe generated at each control section position, a smooth transition surface between the cross-sectional profiles of the air blowing pipe is generated in sequence to generate the air blowing pipe.

[0033] Furthermore, the specific implementation method of step S3.1 includes:

[0034] Step S3.1.1: Define the governing equations for the two-dimensional quartic curve, as shown in the following expression:

[0035] (1)

[0036] Where: 0≤t≤1, is the independent variable of the equation; and These are the x-component equations and y-component equations of the two-dimensional quartic curve at the corresponding t values, respectively. , , , , These are the coordinates of the five control points of the equation, specifically the coordinates of the 1st, 2nd, 3rd, 4th, and 5th control points. The shape of the curve is generated by controlling these five control points.

[0037] Step S3.1.2, set the coordinates of the five control points as follows:

[0038] Set the coordinates of the center point of the air inlet as the coordinates of the first control point. Set the coordinates of the center point of the starting position of the fan section duct as the coordinates of the 5th control point. ;

[0039] Coordinates of the second control point Coordinates of the 3rd control point and the coordinates of the 4th control point The setting method is as follows: it is determined by setting the controllable parameters La1, Lb1, and Lc1, specifically:

[0040] The coordinates at a point La1, perpendicular to the end face of the air outlet and at a distance from the center point of the air outlet, are set as the coordinates of the second control point. ;

[0041] The coordinates at a point perpendicular to the plane of the fan section duct's starting position and at a distance from the center point Lb1 of the fan section duct's starting position are set as the coordinates of the 4th control point. ;

[0042] The coordinates of the point Lc1, located vertically at the midpoint of the line connecting the second and fourth control points, are designated as the coordinates of the third control point. ;

[0043] Step S3.1.3: Substitute the coordinates of the five control points set in step S3.1.2 into the two-dimensional quartic curve control equation, and then transform the two-dimensional quartic curve control equation into a three-dimensional quartic curve control equation, as shown in the following expression:

[0044] (2)

[0045] in: , and , respectively, are the x-component equations, y-component equations, and x-component equations of the three-dimensional quartic curve control equations at the corresponding t value; θ is the acute angle between the air inlet and the vertical direction; The length of the chord; For the exhibition length; These are the coordinates of the first control point, and also the coordinates of the center point of the air inlet; These are the coordinates of the 5th control point, and also the coordinates of the center point of the starting position of the fan section duct;

[0046] Step S3.1.4: Based on the three-dimensional quartic curve control equation, the center line of the air blowing pipe from the center point of the air blowing port to the center point of the starting position of the fan section pipe is generated by setting the controllable parameters La1, Lb1, and Lc1.

[0047] Furthermore, in step S3.2, when selecting control nodes, the density of control nodes is adjusted according to the curvature change of the centerline of the air blowing pipe, and the density is appropriately increased in areas with drastic curvature changes.

[0048] Furthermore, in step S3.3, for each control node, a local coordinate system is established with the x′ axis along the centerline of the air blowing pipe at that control node, the y′ axis perpendicular to the x′ axis and parallel to the global coordinate system xy plane, and the z′ axis parallel to the global coordinate system z axis. Using the local coordinate system created at each control node as the reference coordinate system, the air blowing pipe cross-sectional profile is created on the corresponding control section using a hyperelliptic function. The specific creation method is as follows:

[0049] Step S3.3.1, the expression for the hyperelliptic function is as follows:

[0050] (3)

[0051] Where: a, b, and n are all hyperellipse parameters; a is the length of the major semi-axis of the hyperellipse; b is the length of the minor semi-axis of the hyperellipse; n is the hyperellipse shape control parameter; when n is 2, the hyperellipse function is an ellipse equation, and as n increases, the function shape approximates a rectangle.

[0052] Step S3.3.2: Convert the hyperelliptic function expression into parametric form. The curve equation in the first quadrant is:

[0053] (4)

[0054] Where: 0≤t≤1 is the independent variable of the equation; c is the chord length;

[0055] The values ​​of a and b are determined by the following formula:

[0056] (5)

[0057] (6)

[0058] Where: x t Let x be the relative position of the control node on the centerline of the air blowing pipe, 0 ≤ x t ≤1, specifically, the relative positions of the control nodes located at the starting and ending points of the air blowing duct centerline are 0 and 1 respectively. The relative positions of the control nodes located between the starting and ending points of the air blowing duct centerline are determined according to the ratio of their distance from the starting point to the length of the air blowing duct centerline.

[0059] A is 0.5 times the span, B is the radius of the fan section duct, C is 0.5 times the air outlet size, x c For controllable parameters, k represents the relative position of the control node at the point where the changes in a and b are most drastic along the centerline of the blowing pipe. a k is the control parameter for the degree of change of a. a The larger the value of a in x, the better. c The more drastic the change at a point, the more k b k is the control parameter for the degree of change of b. b The larger the value of b in x c The more drastic the change;

[0060] The governing equations for the hyperelliptical shape control parameter n are as follows:

[0061] (7)

[0062] (8)

[0063] (9)

[0064] Where D and E are intermediate parameters, and B1 is a controllable parameter; by controlling the controllable parameter B1, the variation of the control parameter n of the hyperelliptical shape of different control sections can be adjusted.

[0065] Step S3.3.2, based on the curve equation in the first quadrant, by adjusting the control parameter k a Control parameter k b Controllable parameter B1 and controllable parameter x c Configure settings to generate a curve representing the cross-sectional profile of the air blowing pipe in the first quadrant;

[0066] Step S3.3.3: Symmetrically reflect the curve in the first quadrant with respect to the x′z′ plane to obtain the curve in the fourth quadrant; symmetrically reflect the curve in the first quadrant with respect to the x′y′ plane to obtain the curve in the second quadrant; symmetrically reflect the curve in the fourth quadrant with respect to the x′y′ plane to obtain the curve in the third quadrant.

[0067] The curves in the first quadrant, the second quadrant, the third quadrant, and the fourth quadrant are connected end to end to form the cross-sectional profile of the air blowing pipe at the control node.

[0068] The parametric modeling method for cooperative jet wings of high-altitude long-endurance unmanned aerial vehicles provided by this invention has the following advantages:

[0069] This invention addresses the problems of lack of parametric modeling methods for the internal pipes of collaborative jet devices in current engineering applications, reliance on experience in the design of traditional collaborative jet devices, complexity in internal pipe modeling, and difficulty in systematically controlling variables. It constructs an integrated parametric modeling system for wing shape and internal pipes, which can significantly improve the efficiency of collaborative jet device model construction, accelerate the subsequent wing optimization iteration speed, and provide reliable technical support for designing collaborative jet wings with excellent aerodynamic performance. Attached Figure Description

[0070] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. 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.

[0071] Figure 1 A flowchart of a parametric modeling method for a cooperative jet wing for a high-altitude long-endurance UAV provided by the present invention;

[0072] Figure 2 The clean airfoil section without the coordinating jet device and its cross-sectional geometry of NACA6415 airfoil;

[0073] Figure 3 The four-stage control curve diagram of three parameters provided in the embodiments of the present invention;

[0074] Figure 4This is a schematic diagram of the cooperative jet airfoil generated in an embodiment of the present invention;

[0075] Figure 5 This is a schematic diagram of the synergistic jet wing generated in an embodiment of the present invention;

[0076] Figure 6 This is a side view of the synergistic jet wing generated according to an embodiment of the present invention;

[0077] Figure 7 for Figure 6 Cross-sectional views of various sections of the synergistic jet wing. Detailed Implementation

[0078] To make the technical problems solved, the technical solutions, and the beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the invention.

[0079] This invention addresses the problems of the lack of parametric modeling methods for the internal pipes of collaborative jet devices in current engineering applications, the excessive reliance on experience and intuition in the design of traditional collaborative jet devices, the complexity of internal pipe modeling, the numerous control variables, and the inability to systematically and accurately generate collaborative jet device models. It constructs an integrated parametric modeling system for wing shape and internal pipes, which can significantly improve the efficiency of collaborative jet device model construction, accelerate the subsequent wing optimization iteration speed, and provide reliable technical support for designing collaborative jet wings with excellent aerodynamic performance.

[0080] Example 1:

[0081] See Figure 1 This embodiment provides a parametric modeling method for cooperative jet wings of high-altitude long-endurance unmanned aerial vehicles (UAVs), including the following steps S1 to S3:

[0082] Step S1: Establish a global coordinate system with the chord direction of the wing as the x-axis, the normal direction as the y-axis, and the spanwise direction as the z-axis; given a reference airfoil, set the basic parameters of the wing, the air inlet parameters, and the air inlet parameters; under the global coordinate system, based on the reference airfoil, the basic parameters of the wing, the air inlet parameters, and the air inlet parameters, generate a three-dimensional cooperative jet wing section shape with air inlets and air inlets, and complete the parametric modeling of the wing shape;

[0083] Step S2: Determine the fan section pipe parameters based on the duct fan parameters to complete the parametric modeling of the fan section pipe.

[0084] Step S3: Under the constraints of the wing shape obtained from the modeling, with the air inlet, air inlet and fan section pipe as the boundary, and based on the pipe centerline control parameters and pipe section parameters, the air inlet pipe and air inlet pipe are generated respectively to complete the parametric modeling of the internal pipes, and then the cooperative jet wing is modeled.

[0085] As one specific implementation method, step S1 is specifically implemented by including:

[0086] Step S1.1, the basic parameters of the wing include chord length and span; the parameters of the air inlet include air inlet position parameters and air inlet size parameters; the parameters of the air intake include air intake position parameters and air intake size parameters; wherein, the air inlet position parameter is the relative position of the air inlet from the leading edge of the airfoil along the x-direction, and the air inlet size parameter is the ratio of the downward length of the air inlet perpendicular to the airfoil surface to the chord length; the air intake position parameter is the relative position of the air inlet from the leading edge of the airfoil along the x-direction, and the air intake size parameter is the ratio of the downward length of the air intake perpendicular to the airfoil surface to the chord length.

[0087] Step S1.2: Create an air inlet on the upper surface of the reference airfoil according to the air inlet position parameters and air inlet size parameters; create an air inlet on the upper surface of the reference airfoil according to the air inlet position parameters and air inlet size parameters; the downward direction of the air inlet and the air inlet is along the normal of the airfoil surface.

[0088] Step S1.3: On the upper surface of the reference airfoil, determine and cut off the airfoil profile located between the air inlet and the air inlet; the remaining uncut airfoil profile of the reference airfoil is called the remaining airfoil profile.

[0089] Step S1.4: Shift the cut-off airfoil profile downwards so that the left endpoint of the airfoil profile aligns with the lower endpoint of the air inlet; then rotate the airfoil profile with the left endpoint as the center so that the right side of the airfoil profile passes through the lower endpoint of the air inlet; cut off the portion of the airfoil profile that extends beyond the lower endpoint of the air inlet. At this point, the airfoil profile located between the lower endpoint of the air inlet and the lower endpoint of the air inlet is the target airfoil profile.

[0090] Step S1.5: The target airfoil profile is combined with the remaining airfoil profile of the reference airfoil to form the two-dimensional cooperative jet airfoil;

[0091] Step S1.6: Stretch the two-dimensional cooperative jet airfoil according to the span parameter to obtain the three-dimensional cooperative jet airfoil section shape.

[0092] As one specific implementation method, step S2 is specifically implemented by including:

[0093] Step S2.1: Determine the fan section pipe parameters based on the duct fan parameters; wherein, the duct fan parameters include the duct fan size parameters and position parameters; the fan section pipe parameters include the diameter of the fan section pipe, the coordinates of the starting position center point, and the length of the fan section pipe;

[0094] The specific determination method is as follows: based on the duct fan size parameters and position parameters, determine the diameter of the fan section pipe and the coordinates of the starting center point; combine the duct fan size parameters to determine the diameter and length of the fan section pipe;

[0095] Step S2.2, based on the fan section duct parameters, complete the parametric modeling of the fan section duct, including:

[0096] At the starting position of the fan segment duct, a plane is created perpendicular to the chord line; in the plane, a circular cross-section is drawn with the center point of the starting position as the center and the diameter of the fan segment duct as the diameter; the circular cross-section is stretched to the length of the fan segment duct to generate the fan segment duct; the fan segment duct is a circular duct.

[0097] In this invention, the principle of parametric modeling of the air blowing pipe is the same as that of parametric modeling of the air intake pipe. Therefore, taking the parametric modeling method of the air blowing pipe as an example, it includes steps S3.1 to S3.3:

[0098] Step S3.1: Fix the center point of the air inlet and the center point of the starting position of the fan section pipe, and use the controllable generation algorithm of the air pipe center line to generate the air pipe center line between the center point of the air inlet and the center point of the starting position of the fan section pipe.

[0099] Step S3.1.1: Define the governing equations for the two-dimensional quartic curve, as shown in the following expression:

[0100] (1)

[0101] Where: 0≤t≤1, is the independent variable of the equation; and These are the x-component equations and y-component equations of the two-dimensional quartic curve at the corresponding t values, respectively. , , , , These are the coordinates of the five control points of the equation, specifically the coordinates of the 1st, 2nd, 3rd, 4th, and 5th control points. The shape of the curve is generated by controlling these five control points.

[0102] Step S3.1.2, set the coordinates of the five control points as follows:

[0103] Set the coordinates of the center point of the air inlet as the coordinates of the first control point. Set the coordinates of the center point of the starting position of the fan section duct as the coordinates of the 5th control point. ;

[0104] Coordinates of the second control point Coordinates of the 3rd control point and the coordinates of the 4th control point The setting method is as follows: it is determined by setting the controllable parameters La1, Lb1, and Lc1, specifically:

[0105] The coordinates at a point La1, perpendicular to the end face of the air outlet and at a distance from the center point of the air outlet, are set as the coordinates of the second control point. ;

[0106] The coordinates at a point perpendicular to the plane of the fan section duct's starting position and at a distance from the center point Lb1 of the fan section duct's starting position are set as the coordinates of the 4th control point. ;

[0107] The coordinates of the point Lc1, located vertically at the midpoint of the line connecting the second and fourth control points, are designated as the coordinates of the third control point. ;

[0108] Step S3.1.3: Substitute the coordinates of the five control points set in step S3.1.2 into the two-dimensional quartic curve control equation, and then transform the two-dimensional quartic curve control equation into a three-dimensional quartic curve control equation, as shown in the following expression:

[0109] (2)

[0110] in: , and , respectively, are the x-component equations, y-component equations, and x-component equations of the three-dimensional quartic curve control equations at the corresponding t value; θ is the acute angle between the air inlet and the vertical direction; The length of the chord; For the exhibition length; These are the coordinates of the first control point, and also the coordinates of the center point of the air inlet; These are the coordinates of the 5th control point, and also the coordinates of the center point of the starting position of the fan section duct;

[0111] Step S3.1.4: Based on the three-dimensional quartic curve control equation, the center line of the air blowing pipe from the center point of the air blowing port to the center point of the starting position of the fan section pipe is generated by setting the controllable parameters La1, Lb1, and Lc1.

[0112] Step S3.2: Select several control nodes on the center line of the air blowing pipe, and generate a control section perpendicular to the center line of the air blowing pipe at each control node, thereby controlling the shape change of the air blowing pipe along the center line of the air blowing pipe; when selecting control nodes, the density of control nodes is adjusted according to the curvature change of the center line of the air blowing pipe, and the density is appropriately increased in areas with drastic curvature changes.

[0113] Step S3.3: For each control section, a hyperelliptic function is used to generate the cross-sectional profile of the air blowing pipe. The parameters of the hyperelliptic function used for each control section are continuously controlled along the center line of the air blowing pipe to ensure a smooth transition of the air blowing pipe. For the cross-sectional profiles of the air blowing pipe generated at each control section position, a smooth transition surface between the cross-sectional profiles of the air blowing pipe is generated in sequence to generate the air blowing pipe.

[0114] As a specific implementation method, in step S3.3, for each control node, a local coordinate system is established with the x′ axis along the centerline of the air blowing pipe at that control node, the y′ axis perpendicular to the z′ axis and parallel to the global coordinate system xy plane, and the z′ axis parallel to the global coordinate system z axis. Using the local coordinate system created at each control node as a reference coordinate system, the air blowing pipe cross-sectional profile is created on the corresponding control section using a hyperelliptic function. The specific creation method is as follows:

[0115] Step S3.3.1, the expression for the hyperelliptic function is as follows:

[0116] (3)

[0117] Where: a, b, and n are all hyperellipse parameters; a is the length of the major semi-axis of the hyperellipse; b is the length of the minor semi-axis of the hyperellipse; n is the hyperellipse shape control parameter; when n is 2, the hyperellipse function is an ellipse equation, and as n increases, the function shape approximates a rectangle.

[0118] Step S3.3.2: Convert the hyperelliptic function expression into parametric form. The curve equation in the first quadrant is:

[0119] (4)

[0120] Where: 0≤t≤1 is the independent variable of the equation; c is the chord length;

[0121] The values ​​of a and b are determined by the following formula:

[0122] (5)

[0123] (6)

[0124] Where: x tLet x be the relative position of the control node on the centerline of the air blowing pipe, 0 ≤ x t ≤1, specifically, the relative positions of the control nodes located at the starting and ending points of the air blowing duct centerline are 0 and 1 respectively. The relative positions of the control nodes located between the starting and ending points of the air blowing duct centerline are determined according to the ratio of their distance from the starting point to the length of the air blowing duct centerline.

[0125] A is 0.5 times the span, B is the radius of the fan section duct, C is 0.5 times the air outlet size, x c For controllable parameters, k represents the relative position of the control node at the point where the changes in a and b are most drastic along the centerline of the blowing pipe. a k is the control parameter for the degree of change of a. a The larger the value of a in x, the better. c The more drastic the change at a point, the more k b k is the control parameter for the degree of change of b. b The larger the value of b in x c The more drastic the change;

[0126] The governing equations for the hyperelliptical shape control parameter n are as follows:

[0127] (7)

[0128] (8)

[0129] (9)

[0130] Where D and E are intermediate parameters, and B1 is a controllable parameter; by controlling the controllable parameter B1, the variation of the control parameter n of the hyperelliptical shape of different control sections can be adjusted.

[0131] Step S3.3.2, based on the curve equation in the first quadrant, by adjusting the control parameter k a Control parameter k b Controllable parameter B1 and controllable parameter x c Configure settings to generate a curve representing the cross-sectional profile of the air blowing pipe in the first quadrant;

[0132] Step S3.3.3: Symmetrically reflect the curve in the first quadrant with respect to the x′z′ plane to obtain the curve in the fourth quadrant; symmetrically reflect the curve in the first quadrant with respect to the x′y′ plane to obtain the curve in the second quadrant; symmetrically reflect the curve in the fourth quadrant with respect to the x′y′ plane to obtain the curve in the third quadrant.

[0133] The curves in the first quadrant, the second quadrant, the third quadrant, and the fourth quadrant are connected end to end to form the cross-sectional profile of the air blowing pipe at the control node.

[0134] To address the issues of insufficient parametric modeling methods for the internal pipes of collaborative jet devices and their complex morphological changes, this invention presents a parametric modeling method for collaborative jet wings designed for high-altitude long-endurance UAVs. This method solves the problem of insufficient characterization of the internal pipe shape in current collaborative jet research and provides technical support for designing collaborative jet wings with excellent aerodynamic performance.

[0135] Example 2:

[0136] Using the NACA6415 airfoil as the reference airfoil in this embodiment, this airfoil is commonly used as a reference airfoil for cooperative jet research, and its geometry is as follows: Figure 2 As shown.

[0137] Set the optimization design parameters for airfoil optimization design, including chord length c and span. The parameters include: air outlet location and size; air inlet location and size; coordinates of the center point of the starting position of the circular pipe; radius and length of the circular pipe; control parameters for the air outlet and the air inlet; and control parameters for the air outlet. The control parameters for the air outlet include controllable parameters La1, Lb1, Lc1, and control parameter k. a Control parameter k b Controllable parameter B1 and controllable parameter x c The control parameters for the intake pipeline include controllable parameters La2, Lb2, Lc2, and control parameter k. c Control parameter k d Controllable parameter B2 and controllable parameter x x ;

[0138] In the current round of optimization design, assume the above optimization design parameters are assigned the following values:

[0139] The chord length c is 1000mm, and the aspect ratio is... The diameter is 500mm, the air outlet position is 0.025, the air outlet size is 0.0065, the air inlet position is 0.92, the air inlet size is 0.008, the center point coordinates of the starting position of the circular pipe are (0.4, 0.05), the radius of the circular pipe is 0.03, and the length of the circular pipe is 0.2; in this embodiment, the circular pipe represents the fan section pipe. The control parameters of the air blowing pipe are assigned as follows: La1: 0.06, Lb1: 0.19, Lc1: -0.05, x c 0.55, k a :8,k b : 6, B1: 0.0435; The intake pipe control parameters are assigned as follows: La2: 0.08, Lb2: 0.09, Lc2: -0.035, x x 0.5, k c :8,k d:6, B2:0.0435.

[0140] Among the parameters above, those without units are relative parameters. The actual value of the length parameter is the relative parameter multiplied by the chord length. For example, the actual size of the air inlet = air inlet size × chord length = 0.0065 × 1000 mm = 6.5 mm, and the coordinates of the center point of the starting position of the circular pipe are (0.4 × 1000 mm, 0.05 × 1000 mm) = (400 mm, 50 mm). La1, Lb1, and Lc1 are three parameters that control the centerline of the air inlet. The centerline of the air inlet generated by the current parameters and the curve of the centerline of the air inlet generated by modifying the parameters are shown below. Figure 3 As shown. x c k a k b B1 are parameters controlling the hyperelliptical shape of each cross-section of the air blowing pipe, where x c This represents the location where the hyperellipse changes most drastically along the centerline of the air blowing pipe, with the air outlet as its vertex. La2, Lb2, and Lc2 are three parameters controlling the centerline of the air blowing pipe. x k c k d B2 are parameters controlling the hyperelliptical shape of each cross-section of the intake pipe, where x x The location where the hyperellipse changes most drastically along the centerline of the intake duct with the intake port as the vertex.

[0141] Based on the optimized design parameters with the above values, the specific steps for creating the cooperative jet wing are as follows:

[0142] Step 1: Establish a global coordinate system with the chord direction of the wing as the x-axis, the normal direction as the y-axis, and the spanwise direction as the z-axis. Place the NACA6415 reference airfoil within this global coordinate system;

[0143] Step 2, create the 3D cooperative jet airfoil shape with an air inlet and an air intake:

[0144] On the upper surface of the reference airfoil, at the position of the air inlet x1=0.025, and the air inlet size d c The air inlet is generated using two parameters: x = 0.0065. The air inlet is located at x = 25 mm on the upper surface of the airfoil, with its downward direction along the normal to the airfoil surface. The air inlet size is 6.5 mm. Furthermore, the air inlet position x1 is its relative position to the leading edge of the airfoil along the x-direction, and the air inlet size d... c It is the ratio of the downward length of the air inlet perpendicular to the airfoil surface to the chord length.

[0145] Based on the same principle, using the air inlet position x2=0.92 and the air inlet size d... xThe two parameters =0.008 generate the air intake. The air intake is located at x=920mm on the upper surface of the airfoil. The downward direction of the air intake is along the normal of the airfoil, and the size of the air intake is 8mm.

[0146] On the upper surface of the reference airfoil, the airfoil profile located between the air inlet and the air inlet is determined and truncated; the truncated airfoil profile is translated downwards so that the left endpoint of the airfoil profile is aligned with the lower endpoint of the air inlet; then the airfoil profile is rotated around the left endpoint of the airfoil profile so that the right side of the airfoil profile passes through the lower endpoint of the air inlet; the portion of the airfoil profile extending beyond the lower endpoint of the air inlet is truncated. At this point, the airfoil profile located between the lower endpoint of the air inlet and the lower endpoint of the air inlet is the target airfoil profile.

[0147] The target airfoil profile, combined with the remaining airfoil profile of the reference airfoil, forms as follows: Figure 4 The two-dimensional synergistic jet airfoil shown;

[0148] This two-dimensional co-jet airfoil is stretched to a length of 500 mm to obtain the three-dimensional co-jet airfoil section shape;

[0149] Step 3, create the fan segment duct, i.e., the circular duct:

[0150] At the center point (400mm, 50mm) of the starting position of the circular pipe, create a plane perpendicular to the chord. On this plane, draw a circular cross section with the center point (400mm, 50mm) of the starting position of the circular pipe as the center and the radius of the circular pipe as 30mm. Extrude the circular cross section to a length of 200mm, which is the length of the circular pipe, to complete the creation of the circular pipe.

[0151] Step 4, Create the air blowing pipe:

[0152] Step 4.1: Using the quartic curve control equation proposed in this invention, the centerline of the air blowing pipe is generated through five control points. The specific implementation of this step is the same as steps S3.1.1 to S3.1.4 in Embodiment 1, and will not be repeated here. Its basic principle is as follows: five control points are selected: the center point of the air blowing port and the center point of the starting position of the circular pipe are two basic control points. The remaining three control points are determined by setting three control parameters, thereby achieving control over the overall shape of the air blowing pipe.

[0153] Step 4.2: After creating the centerline of the air blowing pipe using the above method, select several control nodes on the centerline of the air blowing pipe. In this embodiment, 23 control nodes are arranged according to the curvature distribution, and a control section perpendicular to the centerline of the air blowing pipe is created at each control node to control the shape change of the air blowing pipe along the centerline of the air blowing pipe. The density of the control nodes is adjusted according to the curvature change of the centerline of the air blowing pipe, and the density is appropriately increased in areas with drastic curvature changes.

[0154] Step 4.3: For each control section, a hyperelliptic function is used to generate the cross-sectional profile of the air blowing pipe, achieving precise control of the air blowing pipe's shape. For the air blowing pipe cross-sectional profiles generated at each control section position, smooth transition surfaces between the air blowing pipe cross-sectional profiles are generated sequentially, thereby generating the air blowing pipe. The specific implementation method of this step is the same as that of steps S3.3.1 to S3.3.3 in Embodiment 1, and will not be repeated here.

[0155] Finally, using the same method described above for creating the blowing pipe, generate the suction pipe.

[0156] The intake duct, intake pipe, and fan section duct constitute the internal duct of the coordinated jet.

[0157] By adjusting the above-mentioned optimized design parameters, collaborative jet devices of different shapes can be quickly generated. The collaborative jet device generated in this embodiment is as follows: Figures 5-7 As shown.

[0158] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A parametric modeling method for cooperative jet wing of a high-altitude long-endurance unmanned aerial vehicle (UAV), characterized in that, Includes the following steps: Step S1: Establish a global coordinate system with the wing chord direction as the x-axis, the normal direction as the y-axis, and the spanwise direction as the z-axis; Given a reference airfoil, set the basic parameters of the wing, the parameters of the air inlet and the air inlet; in the global coordinate system, based on the reference airfoil, the basic parameters of the wing, the parameters of the air inlet and the parameters of the air inlet, generate a three-dimensional co-current jet wing section shape with air inlet and air inlet, and complete the parametric modeling of the wing shape; Step S2: Determine the fan section pipe parameters based on the duct fan parameters to complete the parametric modeling of the fan section pipe. Step S3: Under the constraints of the wing shape obtained from the modeling, with the air inlet, air inlet and fan section pipe as the boundary, and based on the pipe centerline control parameters and pipe section parameters, the air inlet pipe and air inlet pipe are generated respectively to complete the parametric modeling of the internal pipes, and then the cooperative jet wing is modeled.

2. The method for parametric modeling of cooperative jet wings for high-altitude long-endurance unmanned aerial vehicles according to claim 1, characterized in that, The specific implementation method of step S1 includes: Step S1.1, the basic parameters of the wing include chord length and span; the air inlet parameters include air inlet position parameters and air inlet size parameters; the air intake parameters include air intake position parameters and air intake size parameters; Step S1.2: Create an air inlet on the upper surface of the reference airfoil according to the air inlet position parameters and air inlet size parameters; create an air inlet on the upper surface of the reference airfoil according to the air inlet position parameters and air inlet size parameters; the downward direction of the air inlet and the air inlet is along the normal of the airfoil surface. Step S1.3: On the upper surface of the reference airfoil, determine and cut off the airfoil profile located between the air inlet and the air inlet; the remaining uncut airfoil profile of the reference airfoil is called the remaining airfoil profile. Step S1.4: Shift the cut-off airfoil profile downwards so that the left endpoint of the airfoil profile aligns with the lower endpoint of the air inlet; then rotate the airfoil profile with the left endpoint as the center so that the right side of the airfoil profile passes through the lower endpoint of the air inlet; cut off the portion of the airfoil profile that extends beyond the lower endpoint of the air inlet. At this point, the airfoil profile located between the lower endpoint of the air inlet and the lower endpoint of the air inlet is the target airfoil profile. Step S1.5: The target airfoil profile is combined with the remaining airfoil profile of the reference airfoil to form the two-dimensional cooperative jet airfoil; Step S1.6: Stretch the two-dimensional cooperative jet airfoil according to the span parameter to obtain the three-dimensional cooperative jet airfoil section shape.

3. The method for parametric modeling of cooperative jet wings for high-altitude long-endurance unmanned aerial vehicles according to claim 2, characterized in that, The position parameter of the air inlet is its relative position from the leading edge of the airfoil along the x-direction, and the size parameter of the air inlet is the ratio of the downward length of the air inlet perpendicular to the airfoil surface to the chord length; the position parameter of the air inlet is its relative position from the leading edge of the airfoil along the x-direction, and the size parameter of the air inlet is the ratio of the downward length of the air inlet perpendicular to the airfoil surface to the chord length.

4. The method for parametric modeling of cooperative jet wings for high-altitude long-endurance unmanned aerial vehicles according to claim 1, characterized in that, The specific implementation method of step S2 includes: Step S2.1: Determine the fan section pipe parameters based on the duct fan parameters; wherein, the duct fan parameters include the duct fan size parameters and position parameters; the fan section pipe parameters include the diameter of the fan section pipe, the coordinates of the starting position center point, and the length of the fan section pipe; The specific determination method is as follows: based on the duct fan size parameters and position parameters, determine the diameter of the fan section pipe and the coordinates of the starting center point; combine the duct fan size parameters to determine the diameter and length of the fan section pipe; Step S2.2, based on the fan section duct parameters, complete the parametric modeling of the fan section duct, including: At the starting position of the fan segment duct, a plane is created perpendicular to the chord line; in the plane, a circular cross-section is drawn with the center point of the starting position as the center and the diameter of the fan segment duct as the diameter; the circular cross-section is stretched to the length of the fan segment duct to generate the fan segment duct; the fan segment duct is a circular duct.

5. The method for parametric modeling of cooperative jet wings for high-altitude long-endurance unmanned aerial vehicles according to claim 1, characterized in that, In step S3, the principle of parametric modeling of the blowing pipe is the same as that of parametric modeling of the suction pipe.

6. The method for parametric modeling of cooperative jet wings for high-altitude long-endurance unmanned aerial vehicles according to claim 1, characterized in that, The method for parametric modeling of the air blowing pipe is as follows: Step S3.1: Fix the center point of the air inlet and the center point of the starting position of the fan section pipe, and use the controllable generation algorithm of the air pipe center line to generate the air pipe center line between the center point of the air inlet and the center point of the starting position of the fan section pipe. Step S3.2: Select several control nodes on the center line of the air blowing pipe, and generate a control section perpendicular to the center line of the air blowing pipe at each control node, thereby controlling the shape change of the air blowing pipe along the center line of the air blowing pipe. Step S3.3: For each control section, a hyperelliptic function is used to generate the cross-sectional profile of the air blowing pipe. The parameters of the hyperelliptic function used for each control section are continuously controlled along the center line of the air blowing pipe to ensure a smooth transition of the air blowing pipe. For the cross-sectional profiles of the air blowing pipe generated at each control section position, a smooth transition surface between the cross-sectional profiles of the air blowing pipe is generated in sequence to generate the air blowing pipe.

7. A parametric modeling method for cooperative jet wing of a high-altitude long-endurance UAV according to claim 6, characterized in that, The specific implementation method of step S3.1 includes: Step S3.1.1: Define the governing equations for the two-dimensional quartic curve, as shown in the following expression: （1） Where: 0≤t≤1, is the independent variable of the equation; and These are the x-component equations and y-component equations of the two-dimensional quartic curve at the corresponding t values, respectively. , , , , These are the coordinates of the five control points of the equation, specifically the coordinates of the 1st, 2nd, 3rd, 4th, and 5th control points. The shape of the curve is generated by controlling these five control points. Step S3.1.2, set the coordinates of the five control points as follows: Set the coordinates of the center point of the air inlet as the coordinates of the first control point. Set the coordinates of the center point of the starting position of the fan section duct as the coordinates of the 5th control point. ; Coordinates of the second control point Coordinates of the 3rd control point and the coordinates of the 4th control point The setting method is as follows: it is determined by setting the controllable parameters La1, Lb1, and Lc1, specifically: The coordinates at a point La1, perpendicular to the end face of the air outlet and at a distance from the center point of the air outlet, are set as the coordinates of the second control point. ; The coordinates at a point perpendicular to the plane of the fan section duct's starting position and at a distance from the center point Lb1 of the fan section duct's starting position are set as the coordinates of the 4th control point. ; The coordinates of the point Lc1, located vertically at the midpoint of the line connecting the second and fourth control points, are designated as the coordinates of the third control point. ; Step S3.1.3: Substitute the coordinates of the five control points set in step S3.1.2 into the two-dimensional quartic curve control equation, and then transform the two-dimensional quartic curve control equation into a three-dimensional quartic curve control equation, as shown in the following expression: （2） in: , and , respectively, are the x-component equations, y-component equations, and x-component equations of the three-dimensional quartic curve control equations at the corresponding t value; θ is the acute angle between the air inlet and the vertical direction; The length of the chord; For the exhibition length; These are the coordinates of the first control point, and also the coordinates of the center point of the air inlet; These are the coordinates of the 5th control point, and also the coordinates of the center point of the starting position of the fan section duct; Step S3.1.4: Based on the three-dimensional quartic curve control equation, the center line of the air blowing pipe from the center point of the air blowing port to the center point of the starting position of the fan section pipe is generated by setting the controllable parameters La1, Lb1, and Lc1.

8. A parametric modeling method for cooperative jet wing of a high-altitude long-endurance UAV according to claim 6, characterized in that, In step S3.2, when selecting control nodes, the density of control nodes is adjusted according to the curvature change of the centerline of the air blowing pipe, and the density is appropriately increased in areas with drastic curvature changes.

9. A parametric modeling method for cooperative jet wing of a high-altitude long-endurance UAV according to claim 6, characterized in that, In step S3.3, for each control node, a local coordinate system is established with the x′ axis along the centerline of the air blowing pipe at that control node, the y′ axis perpendicular to the x′ axis and parallel to the global coordinate system xy plane, and the z′ axis parallel to the global coordinate system z axis. Using the local coordinate system created at each control node as the reference coordinate system, the air blowing pipe cross-sectional profile is created on the corresponding control section using a hyperelliptic function. The specific creation method is as follows: Step S3.3.1, the expression for the hyperelliptic function is as follows: （3） Where: a, b, and n are all hyperellipse parameters; a is the length of the major semi-axis of the hyperellipse; b is the length of the minor semi-axis of the hyperellipse; n is the hyperellipse shape control parameter; when n is 2, the hyperellipse function is an ellipse equation, and as n increases, the function shape approximates a rectangle. Step S3.3.2: Convert the hyperelliptic function expression into parametric form. The curve equation in the first quadrant is: （4） Where: 0≤t≤1 is the independent variable of the equation; c is the chord length; The values ​​of a and b are determined by the following formula: （5） （6） Where: x t Let x be the relative position of the control node on the centerline of the air blowing pipe, 0 ≤ x t ≤1, specifically, the relative positions of the control nodes located at the starting and ending points of the air blowing duct centerline are 0 and 1 respectively. The relative positions of the control nodes located between the starting and ending points of the air blowing duct centerline are determined according to the ratio of their distance from the starting point to the length of the air blowing duct centerline. A is 0.5 times the span, B is the radius of the fan section duct, C is 0.5 times the air outlet size, x c For controllable parameters, k represents the relative position of the control node at the point where the changes in a and b are most drastic along the centerline of the blowing pipe. a k is the control parameter for the degree of change of a. a The larger the value of a in x, the better. c The more drastic the change at a point, the more k b k is the control parameter for the degree of change of b. b The larger the value of b in x c The more drastic the change; The governing equations for the hyperelliptical shape control parameter n are as follows: （7） （8） （9） Where D and E are intermediate parameters, and B1 is a controllable parameter; by controlling the controllable parameter B1, the variation of the control parameter n of the hyperelliptical shape of different control sections can be adjusted. Step S3.3.2, based on the curve equation in the first quadrant, by adjusting the control parameter k a Control parameter k b Controllable parameter B1 and controllable parameter x c Configure settings to generate a curve representing the cross-sectional profile of the air blowing pipe in the first quadrant; Step S3.3.3: Symmetrically reflect the curve in the first quadrant with respect to the x′z′ plane to obtain the curve in the fourth quadrant; symmetrically reflect the curve in the first quadrant with respect to the x′y′ plane to obtain the curve in the second quadrant; symmetrically reflect the curve in the fourth quadrant with respect to the x′y′ plane to obtain the curve in the third quadrant. The curves in the first quadrant, the second quadrant, the third quadrant, and the fourth quadrant are connected end to end to form the cross-sectional profile of the air blowing pipe at the control node.

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