Inverse design method for complex curved shock-onset body based on three-dimensional curved stream surface method

Abstract

The application relates to a complex curved surface shock wave body counter-design method based on a three-dimensional curved flow surface method, and relates to a hypersonic wave body. The complex curved surface shock wave body is provided with a complex curved surface shock wave body lower surface compression profile, a complex curved surface shock wave body upper surface profile and a complex curved surface shock wave body leading edge profile; the complex curved surface shock wave body lower surface profile and the complex curved surface shock wave body upper surface are connected by the complex curved surface shock wave body leading edge profile. A complex curved surface three-dimensional outflow shock wave is specified, and a wave body capture profile is designed; the complex curved surface shock wave is dispersed into a series of initial flow surfaces; shock wave angles, shock wave curvatures and wave rear parameters are solved; a complex shock wave curved surface wave rear flow field is solved, and a compression profile is determined; a wave body upper surface geometric shape is constructed according to design requirements; and the upper and lower surfaces are connected to form a complete complex curved surface shock wave body geometric shape. The method has higher calculation efficiency and higher precision, and provides a wider performance improvement space for aircraft design through free shock wave selection.

Description

Technical Field

[0001] This invention relates to hypersonic waveriders in near space, and more particularly to a method for inverse design of complex curved surface shock waveriders based on the three-dimensional curved flow surface method. Background Technology

[0002] Although significant progress has been made in the research of hypersonic waveriders, and the performance of components is constantly improving, even herringbone waveriders still employ an axisymmetric reference flow field to date, using streamline tracing techniques to obtain the corresponding profile. However, three-dimensional waveriders obtained based on an axisymmetric reference flow field lack lateral flow, exhibiting only directional flow. Studies have shown that the influence of the lateral pressure gradient is non-negligible in the herringbone cone waverider case (Chauffour, ML, and Lewis, MJ, "Corrected Waverider Design for Inlet Applications," 40th AIAA / ASME / SAE / ASEE Joint Propulsion Conference and Exhibit, AIAA, Fort Lauderdale, Florida, 2004, p. 3405. doi:10.2514 / 6.2004-3405.). This effect becomes particularly crucial when combining a hypersonic inlet with a herringbone cone waverider forebody. The non-uniform flow field caused by the lateral pressure gradient significantly degrades the performance of the propulsion system.

[0003] To address this issue, Lewis (Lewis, MJ, and Chauffour, ML, “Shock-based Waverider Design with Pressure Gradient Corrections and Computational Simulations,” Journal of Aircraft, Vol. 42, No. 5, 2005, pp. 1350-1352. doi:10.2514 / 1.13027.) introduced a correction for the lateral pressure gradient to generate a more accurate waverider compression profile. However, research shows that the lateral pressure correction has a relatively small impact on the geometry and cannot fully compensate for the lateral pressure gradient. Lateral flow plays a crucial role in improving aircraft performance. Meanwhile, researchers commonly use the traditional method of characteristics for baseline flow field inversion design, which is not only complex to program but also suffers from poor stability, limiting the range of basic flow field selection and thus reducing the range of waverider geometry.

[0004] Therefore, one of the problems currently limiting the performance of hypersonic waveriders is the lack of a reverse design method for complex curved surface shock waveriders based on the three-dimensional curved flow surface method. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by providing a reverse design method for complex curved surface shock wave riders based on the three-dimensional curved flow surface method. This method enables accurate and rapid solutions for complex flow fields with transverse flow, and applies this solution to the solution of complex curved surface shock wave flow fields to design high-performance wave riders. Furthermore, it utilizes the transverse vortices generated by the transverse flow to obtain wave riders with better aerodynamic performance.

[0006] This invention provides a complex curved surface shock wave rider scheme based on the three-dimensional curved flow surface method, which includes a complex curved surface shock wave rider. The complex curved surface shock wave rider is a curved surface wave rider with lateral flow. By considering the lateral flow in the three-dimensional case to generate lateral vortices, the lift is improved and the drag is reduced, thereby improving the performance of the aircraft. The complex curved surface shock wave rider has a lower surface compression profile, an upper surface profile, and a leading edge profile. The lower surface profile and the upper surface profile of the complex curved surface shock wave rider are transitioned by the leading edge profile.

[0007] This invention includes the following steps:

[0008] 1) Specify the complex surface three-dimensional external flow shock wave according to the design requirements. The complex surface three-dimensional external flow shock wave is specified using non-axisymmetric surface functions such as parametric surface or Bezier surface;

[0009] 2) Design a waverider capture profile in a complex shock wave surface. The profile uses a parametric curve to form a leading edge shape on the shock wave surface that meets the design requirements, and divides the required flow field into the initial complex shock wave surface.

[0010] 3) Discretize the complex curved shock wave along the velocity component direction of the shock wave surface into a series of initial flow surfaces. Based on the external shock wave normal vector and the incoming flow direction of the complex shock wave surface, solve for the local shock wave angle, shock wave curvature, and waveback parameters.

[0011] 4) The shape of the curved flow surface is determined by using the gradient information after the wave, and the flow field parameters after the wave of the corresponding complex shock surface are solved by Euler equations in a three-dimensional streamline coordinate system from a streamline and a feature line in the curved flow surface. Streamline information is extracted from the flow field parameters, and the streamlines emitted from the leading edge profile are combined as the compression profile of the waverider of the complex shock surface.

[0012] 5) Based on the compression profile, construct the upper surface geometry of the hypersonic complex curved surface shock wave rider according to the design requirements; connect the upper and lower surfaces to form a complete complex curved surface shock wave rider geometry;

[0013] In step 4), the curvature of the flow surface is obtained based on the gradient information provided by the three-dimensional curvature shock wave theory.

[0014] The advantages of this invention are:

[0015] 1. This invention utilizes non-axisymmetric surface functions such as parametric surfaces and Bézier surfaces, allowing for the flexible specification of complex three-dimensional external flow shock waves according to actual needs. This better meets design requirements, precisely controls the shape and position of the shock surface and waverider, and thus improves computational accuracy and efficiency. This invention discretizes the complex surface shock wave along the velocity component direction of the shock surface into a series of initial flow surfaces, and then uses the Euler equations in a three-dimensional streamline coordinate system to solve the corresponding complex shock surface backflow field, improving design efficiency. By designing the shock surface and waverider in reverse, design requirements can be better met, resulting in a shock waverider that meets actual needs. This invention employs the three-dimensional curved flow surface method, which can better describe the shape and characteristics of the shock surface, improving computational stability and reliability. This invention uses a compression profile as a basis, connecting the upper and lower surfaces to form a complete geometry of the complex surface shock waverider, thus obtaining a complete waverider design.

[0016] 2. The complex curved surface shock wave rider generated using this method, based on the three-dimensional curved flow surface method, theoretically considers the lateral flow that cannot be ignored in complex curved surface shock wave riders, ensuring that the designed complex curved surface shock wave rider has the same high lift-to-drag ratio as in actual conditions, and achieves inverse design of the flow field for known complex curved surface shock waves. The complex curved surface shock wave rider is a curved surface wave rider with lateral flow. By considering the lateral flow in three dimensions, lateral vortices are generated to increase lift and reduce drag, thereby improving aircraft performance. In addition, the three-dimensional curved flow surface method can fully utilize gradient information, which is more efficient and accurate than the traditional three-dimensional characteristic line method. The obtained basic flow field is no longer limited to a regular flow field, and the more flexible shock wave selection provides a wider range of performance improvement space for aircraft design. The design method of complex curved surface three-dimensional external flow shock wave rider can be applied to multiple engineering fields, including aerospace, automotive, and biomedicine. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the shock wave and leading edge profile in the reference flow field of a complex curved surface shock wave rider scheme based on the three-dimensional curved flow surface method.

[0018] Figure 2 This is a schematic diagram illustrating the principle of the three-dimensional curved flow surface method.

[0019] Figure 3 This is a schematic diagram of the solution process of the three-dimensional curved flow surface method.

[0020] Figure 4 This is a schematic diagram of a complex curved surface shock wave rider scheme based on the three-dimensional curved flow surface method, viewed from below.

[0021] Figure 5 This is a schematic diagram of the overall structure of a complex curved surface shock wave rider based on the three-dimensional curved flow surface method.

[0022] The markings in the figure are as follows: 1 represents a complex curved surface shock wave; 2 represents the leading edge profile of a complex curved surface shock wave; 3 represents the discrete curve of the velocity components of a complex curved surface shock wave along the shock wave surface; 4 represents different curved flow surfaces; 5 represents the leading edge profile of a complex curved surface shock wave waverider; 6 represents the initial flow surface; 7 represents the streamlines in the flow field of a complex curved surface shock wave; 8 represents the compression profile of the upper surface of a complex curved surface shock wave waverider; 9 represents the compression profile of the lower surface of a complex curved surface shock wave waverider; and 10 represents a complex curved surface shock wave waverider. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the following embodiments will be used in conjunction with the accompanying drawings to further illustrate the invention. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0024] like Figure 5 As shown, this embodiment of the invention provides a curved flow surface method for solving the flow field using gradient parameters obtained from three-dimensional curved shock wave theory. The method includes a complex curved surface shock wave rider 10, which is composed of a lower surface compression profile 9, an upper surface compression profile 8, and a leading edge capturing profile 2. The complex curved surface shock wave rider is capable of external wave riding, and the lower surface compression profile 9 and the upper surface compression profile 8 intersect at the leading edge capturing profile 2.

[0025] The main implementation steps of the complex curved surface shock wave rider inverse design method based on the three-dimensional curved flow surface method include:

[0026] 1) such as Figure 1 As shown, a complex surface shock wave 1 is specified according to the design requirements. The complex surface shock wave 1 is specified using non-axisymmetric surface functions such as parametric surfaces or Bezier surfaces. The required parameters such as flow velocity, pressure, and temperature, as well as the shape and intensity requirements of the shock wave, are determined according to the design objectives.

[0027] 2) In Figure 1 The complex surface shock wave 1 shown is designed with a leading edge profile 2 of the complex surface shock wave rider. The profile is obtained by using parametric curves to obtain the curve shape on the shock wave surface that meets the design requirements. The complex surface shock wave 1 is divided by the leading edge profile 2 of the complex surface shock wave rider to obtain the part of the complex surface shock wave required by the complex surface shock wave rider.

[0028] 3) For example Figure 2 As shown, the component directions of the discrete curve 3 of the velocity components along the shock surface of the complex curved surface shock wave 1 are discretized into a series of initial flow surfaces 6. Based on the normal vector of the complex curved surface shock wave and the incoming flow direction, the local shock wave angle, shock wave curvature, and wave back parameters are solved. The corresponding full three-dimensional external compression basic flow field is solved using the three-dimensional curved flow surface method. The solution process is carried out in different curved flow surfaces 4, such as... Figure 3 As shown, based on the shock angle, shock curvature, and waveback parameters at discrete points on the complex curved surface shock wave 1, the leading edge profile 5 of the complex curved surface shock wave within different curved flow surfaces 4 is obtained using the curved flow surface method, as shown in the figure. Figure 4 As shown, by combining all the compression profiles 5 within the curved flow surfaces 4, the corresponding complex curved surface shock wave rider's lower surface compression profile 9 is obtained; the governing equations of the curved flow surface method in the curved flow surface are as follows:

[0029]

[0030]

[0031]

[0032]

[0033]

[0034]

[0035] Where p is the pressure. The direction of flow is M, Mach number is ρ, density is V, flow velocity is w, circumferential velocity is γ, specific heat ratio is γ, streamline is s, and c is c. ± For characteristic lines, The derivative of the pressure along the streamline. and Let be the projection of the derivative of the flow direction along the streamline onto the two directions perpendicular to the streamline, with its unit vector being . and The directions are n and l, and Sl is the rate of change of flow direction perpendicular to the curved flow surface.

[0036] The curved flow surface method solves for the flow parameters at the intersection of streamline 7 and the characteristic line in the complex curved surface shock wave flow field emanating from the initial point based on the governing equations along the streamline and characteristic line directions. It utilizes the gradient parameters of the complex curved surface shock wave 1 obtained from the three-dimensional curved shock wave theory to achieve higher accuracy and efficiency. Unlike existing techniques, this method retains equations containing transverse flow, resulting in flow field parameters and waverider body shapes that better reflect actual conditions.

[0037] (4) Based on the compression profile, the hypersonic complex curved surface shock wave rider is geometrically constructed; according to the volume ratio requirement of the shock wave rider, the compression profile 8 on the upper surface of the complex curved surface shock wave rider is constructed as a plane or a convex surface, so as to obtain the complex curved surface shock wave rider 10 based on the three-dimensional curved flow surface method under the design flight state.

[0038] Inviscid numerical simulations were performed on the complex curved surface shock wave rider designed in this embodiment of the invention, and the results were compared with the calculation results. The errors are shown in the table below. The aerodynamic parameters of the designed complex curved surface shock wave rider are basically consistent with the lift-to-drag ratio and the numerical simulation results.

[0039]

[0040] This invention utilizes a complex curved surface shock waverider scheme based on the three-dimensional curved flow surface method to calculate and inversely design the external flow field of the complex curved surface shock waverider. It allows for the selection of complex curved surface shock waves that better leverage the high lift-to-drag ratio of the waverider, based on design requirements. By rationally designing complex curved surface shock waves, the vortex lift generated by the three-dimensional lateral flow of the airflow can be utilized to improve the waverider's performance, thereby increasing the overall performance of the aircraft. Complex curved surface shock waves broaden the design range of waveriders, providing more options for aircraft structural matching.

[0041] The above embodiments are merely preferred embodiments of the present invention and should not be considered as limiting the scope of the present invention. All equivalent variations and improvements made within the scope of the present invention should still fall within the patent coverage of the present invention.

Claims

1. A method for inverse design of complex curved surface shock wave riders based on the three-dimensional curved flow surface method, characterized in that... Includes the following steps: (1) Specify the complex surface three-dimensional external flow shock wave according to the design requirements. The complex surface three-dimensional external flow shock wave is specified by parametric surface or Bézier surface non-axisymmetric surface function. (2) Design the wave rider capturing profile in the complex shock wave surface. The profile is formed by parametric curves on the shock wave surface to form a leading edge shape that meets the design requirements. The required flow field is segmented in the initial complex shock wave surface. (3) Discretize the complex curved shock wave along the velocity component direction of the shock wave surface into a series of initial flow surfaces. Based on the external shock wave normal vector and the incoming flow direction of the complex shock wave surface, solve the local shock wave angle, shock wave curvature and wave back parameters. Based on the gradient information provided by the three-dimensional curved shock wave theory, obtain the curvature of the flow surface to form a curved flow surface. In the curved flow surface, use the Euler equation of the three-dimensional streamline coordinate system to solve the corresponding complex shock wave surface wave back flow field. Combine the streamlines emanating from the leading edge profile as the compression profile of the complex shock wave surface wave rider. (4) Based on the compression profile, construct the upper surface geometry of the hypersonic complex curved surface shock wave rider according to the design requirements; connect the upper and lower surfaces to form a complete complex curved surface shock wave rider geometry.

2. The inverse design method for complex curved surface shock wave riders based on the three-dimensional curved flow surface method as described in claim 1, characterized in that... In step (3), the backflow field of the corresponding complex shock wave surface is solved using the Euler equations in the three-dimensional streamline coordinate system in the curved flow surface. The streamlines emanating from the leading edge profile are combined as the compression profile of the complex shock wave surface waverider. Specifically, the three-dimensional curved flow surface method is used to solve the corresponding three-dimensional external compression basic flow field. The solution process is carried out in different curved flow surfaces. Based on the shock wave angle, shock wave curvature, and backflow parameters of discrete points on the complex curved surface shock wave, the leading edge profile of the complex curved surface shock waverider in different curved flow surfaces is obtained by using the curved flow surface method. The compression profiles in all curved flow surfaces are combined to obtain the compression profile of the lower surface of the corresponding complex curved surface shock waverider. The governing equations of the curved flow surface method in the curved flow surface are as follows: Where p is the pressure, The direction of flow is given by M, Mach number is given by ρ, density is given by V, flow velocity is given by w, circumferential velocity is given by γ, specific heat ratio is given by γ, and streamline is given by s. For characteristic lines, The derivative of the pressure along the streamline. and Let be the projection of the derivative of the flow direction along the streamline onto the two directions perpendicular to the streamline, with its unit vector being . and The directions are n and l, and Sl is the rate of change of flow direction perpendicular to the curved flow surface.

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