Non-structured hybrid grid generation method for internal flow of rotating machinery with moving and stationary interference surfaces

Abstract

The application discloses a rotating machine inner flow non-structure mixed grid generation method with dynamic and static interference surfaces, and comprises the following steps: reading rotating machine geometric model data by using a geometric engine Open CASCADE, giving boundary attributes of the geometric model, dividing the geometric model into a main body and a secondary body, and giving boundary attributes of the main body and the secondary body; defining symmetric edges and surface edges according to the boundary attributes of the main body and the secondary body, and generating a triangular surface grid on the main body; generating an anisotropic triangular prism unit on the main body according to the triangular surface grid; regenerating a triangular surface grid and a quadrilateral surface grid on the main body according to the triangular prism unit; generating a quadrilateral surface grid on the secondary body according to the quadrilateral surface grid of the main body; generating a hexahedron unit and a pyramid unit on the secondary body according to the quadrilateral surface grid of the secondary body; and generating a tetrahedron unit on the main body according to the pyramid unit.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aero-engine rotating machinery grid generation, and particularly relates to a rotating machinery internal flow unstructured hybrid grid generation method with rotor-stator interference surfaces. BACKGROUND

[0002] Rotating machinery is a device that realizes energy conversion or fluid pressurization through multi-stage rotating motion. Typical applications include turbines, compressors, and steam turbines. These machines usually have complex structural features and flow field characteristics. In areas such as blade tip, film cooling hole, and internal cooling channel, there are high curvature and cross-size variation characteristics. In addition, the interaction between rotating parts and fixed parts (such as stators or vanes) can cause unsteady flow phenomena such as separation flow, secondary flow, leakage flow, and vortex flow. These complex situations bring great challenges to the numerical simulation of rotating machinery.

[0003] Grid generation is a very important step in the above numerical simulation process, and the type, quality, and quantity of the grid will directly affect the accuracy and efficiency of the calculation. Grid generation usually uses structured grid or unstructured grid. Structured grid has the advantages of fast calculation speed and high solving accuracy, but it performs poorly in handling complex geometries and has low automation. Unstructured grid performs well in handling complex geometries, with flexible grid size transition, but has high data storage and computational complexity. Although existing grid generation techniques have made significant progress, there are still many challenges in the field of rotating machinery, including:

[0004] Rotating machinery usually adopts structured grid division, but the structured grid division process requires manual setting of grid topology, involves a lot of manual interaction, and in complex geometries, manually generated grids are time-consuming and prone to errors.

[0005] In the simulation of high Reynolds number fluid flow in rotating machinery, there are anisotropic boundary layer characteristics near the wall surface, and a free shear layer that is not attached to the model boundary. In these cases, the variation rate of the solution variable along the normal and tangential directions in the boundary layer and shear layer can differ by several orders of magnitude. Therefore, it is essential to use reasonably aligned anisotropic grids to accurately capture these flow characteristics.

[0006] In the numerical simulation of multi-stage rotating machinery, the interaction between moving blades and stationary blades leads to very complex flow phenomena in the rotor-stator interference surface region. Since the two-stage blades are in relative motion, it is difficult to ensure consistency in the grid generated at the interface, and interpolation is generally needed to transfer physical information. Unstructured grids are difficult to ensure smooth transition of the flow field. Therefore, it is necessary to improve the accuracy and efficiency of data transfer and achieve efficient and high-quality physical information transfer. SUMMARY

[0007] Based on this, the application provides a rotating machinery internal flow non-structure hybrid grid generation method with dynamic and static interference surfaces to solve the problems in the background art.

[0008] The technical solutions adopted by the embodiments of the application are as follows:

[0009] A rotating machinery internal flow non-structure hybrid grid generation method with dynamic and static interference surfaces comprises the following steps:

[0010] Geometric engine Open CASCADE is used to read rotating machinery geometric model data;

[0011] According to the geometric model data, boundary attributes of the geometric model are given;

[0012] According to the boundary attributes of the geometric model, the geometric model is divided into a main body and a secondary body, and boundary attributes of the main body and the secondary body are given;

[0013] According to the boundary attributes of the main body and the secondary body, symmetric edges and surface edges are defined;

[0014] According to the symmetric edges and the surface edges, triangular surface grids are generated on the main body;

[0015] According to the triangular surface grids, anisotropic triangular prismatic elements are generated on the main body;

[0016] According to the triangular prismatic elements, triangular surface grids and quadrilateral surface grids are regenerated on the main body;

[0017] According to the quadrilateral surface grids of the main body, quadrilateral surface grids are generated on the secondary body;

[0018] According to the quadrilateral surface grids of the secondary body, hexahedral elements and pyramid elements are generated on the secondary body;

[0019] According to the pyramid elements, tetrahedral elements are generated on the main body.

[0020] The technical solutions provided by the embodiments of the application can have the following beneficial effects:

[0021] The application divides the geometric model into a main body and a secondary body, generates non-structure tetrahedral elements in the main body region to adapt to complex geometric shapes, and generates structured hexahedral elements in the secondary body region to improve the accuracy and efficiency of data transmission;

[0022] The application generates anisotropic layered prismatic elements near the wall surface to cope with high flow gradients perpendicular to the wall surface, and proposes an automatic normal regularization method and a quadrilateral grid reconstruction method considering the influence of the boundary layer on the dynamic and static interference surfaces.

[0023] The application provides a hexahedral unit and transition gold tower unit generation method, and realizes adaptation and compatibility of hexahedral, tetrahedral and trilateral prism mixed units by extracting and recombining triangular face grids. BRIEF DESCRIPTION OF DRAWINGS

[0024] The drawings incorporated by reference in the specification and forming a part thereof, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the application.

[0025] Figure 1 It is a flow chart of a rotating machine internal flow unstructured mixed grid generation method with dynamic and static interference surfaces according to an exemplary embodiment.

[0026] Figure 2 It is a compressor geometry model diagram according to an exemplary embodiment.

[0027] Figure 3 It is a geometry model boundary attribute schematic diagram according to an exemplary embodiment.

[0028] Figure 4 It is a main body and secondary body generation schematic diagram according to an exemplary embodiment.

[0029] Figure 5 It is a main body boundary attribute schematic diagram according to an exemplary embodiment.

[0030] Figure 6 It is a secondary body boundary attribute schematic diagram according to an exemplary embodiment.

[0031] Figure 7 It is a main body symmetric edge and surface edge schematic diagram according to an exemplary embodiment.

[0032] Figure 8 It is a secondary body symmetric edge and surface edge schematic diagram according to an exemplary embodiment.

[0033] Figure 9 It is a regenerated symmetric surface face grid schematic diagram according to an exemplary embodiment.

[0034] Figure 10 It is a regenerated symmetric edge line grid schematic diagram according to an exemplary embodiment.

[0035] Figure 11 It is a quadrilateral face grid schematic diagram on the internal dynamic and static interference surface according to an exemplary embodiment.

[0036] Figure 12 It is a generated external dynamic and static interference surface line grid schematic diagram according to an exemplary embodiment.

[0037] Figure 13is a flowchart of generating a hexahedral element according to an exemplary embodiment.

[0038] Figure 14 is a hexahedral and pyramid element diagram according to an exemplary embodiment.

[0039] Figure 15 is an assembling triangular face mesh constraint diagram according to an exemplary embodiment.

[0040] Figure 16 is a hybrid mesh diagram according to an exemplary embodiment.

[0041] Figure 17 is a dynamic-static interference surface structured mesh detail diagram according to an exemplary embodiment. DETAILED DESCRIPTION

[0042] The exemplary embodiments will be described in detail herein with reference to the attached drawings. The following description is made with reference to the accompanying drawings in which like reference numerals refer to like elements, unless the context clearly shows otherwise. The following description of exemplary embodiments is not representative of all embodiments consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with some aspects of the present application as detailed in the appended claims.

[0043] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application. As used in this application and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that the term "and / or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

[0044] Figure 1 is a flowchart of a method for generating an unstructured hybrid mesh inside a rotating machine with dynamic-static interference surfaces according to an exemplary embodiment, as shown in Figure 1 The method can include the following steps:

[0045] S1: reading the rotating machine geometry model data by using the geometry engine Open CASCADE.

[0046] Specifically, the rotating machine geometry model mainly includes the compressor and turbine of a gas turbine, and the present application will take the compressor as an example of a typical rotating machine geometry model for detailed description, as shown in Figure 2The geometric model data includes point, line, face geometric information and topological information, the geometric information includes point coordinates, line parameter equation and face parameter equation, and the topological information includes the dependent relationship of points, lines, faces and bodies, the body is composed of several faces, the face is composed of several lines, and the line is composed of two end points.

[0047] S2: According to the geometric model data, the boundary attribute of the geometric model is given.

[0048] Specifically, as shown in the figure, the external moving and static interference surface, the object surface and the symmetry surface boundary attribute are marked on the face of the geometric model; the boundary attribute of the geometric model is mainly used to establish a mapping relationship with the grid, and is used for subsequent solving calculation; in addition, according to the boundary attribute, specific geometric lines and faces can be found for the processing of the structured grid. Figure 3

[0049] S3: According to the boundary attribute of the geometric model, the geometric model is divided into a main body and a secondary body, and the boundary attribute of the main body and the secondary body is given.

[0050] S31: According to the boundary attribute of the geometric model, a division surface is defined, the division surface is intersected with the geometric model by using a Boolean operation, and two divided geometric bodies are returned as the main body and the secondary body.

[0051] Specifically, as shown in the figure, the center point and the normal of the external moving and static interference surface are calculated by using the geometric engine Open CASCADE, and a point is obtained by translating the center point along the negative direction of the normal by a unit length; a plane is created as a division surface through the point and the normal, then the division surface is intersected with the geometric model by using a Boolean operation, and two divided geometric bodies are returned, the part in the positive direction of the division surface is the main body, and the part in the negative direction of the division surface is the secondary body. Dividing the geometric body into the main body and the secondary body facilitates generating different grid types in different areas of the geometric model, that is, generating unstructured cells in the main body and structured cells in the secondary body. Figure 4 S32: The boundary attribute of the internal moving and static interference surface, the object surface and the symmetry surface is marked on the main body, and the boundary attribute of the internal moving and static interference surface, the external moving and static interference surface, the object surface and the symmetry surface is marked on the secondary body.

[0052] Specifically, the surface where the division surface is located is defined as the internal moving and static interference surface, and the boundary attribute of the remaining surfaces inherits the boundary attribute of the original surface to which they belong,

[0053] as shown in the figure, the boundary attribute of the main body, Figure 5 as shown in the figure, the boundary attribute of the secondary body. Figure 6 S4: According to the boundary attribute of the main body and the secondary body, the symmetry edge and the object surface edge are defined.

[0054] S4: According to the boundary attribute of the main body and the secondary body, the symmetry edge and the object surface edge are defined.​

[0055] Specifically, according to the boundary properties of the main body and the secondary body, mark all edges adjacent to the dynamic-static interference surface and the symmetry surface as symmetry edges, and mark all edges adjacent to the dynamic-static interference surface and the object surface as object surface edges, Figure 7 The main body is shown, Figure 8 The secondary body is shown, in which the edges represented by solid lines are object surface edges, and the edges represented by dashed lines are symmetry edges. According to the symmetry edges and the object surface edges, the line grid of the specified boundary can be specially processed.

[0056] S5: generating a triangular surface grid on the main body according to the symmetry edges and the object surface edges;

[0057] S51: arranging grid points of the same number and uniformly distributed on the object surface edges of the main body, generating a line grid with equal discrete segment numbers, and then generating a line grid of the remaining boundary;

[0058] Specifically, assuming that the parametric curve of the object surface edge is C(t) = (x(t), y(t), z(t)) where t ∈[ P 0 ,P n ], P 0 and P n are the starting point and the ending point of the curve, respectively; the total arc length of the curve is calculated by integration If N points are arranged, then the grid size between adjacent points is ; starting from the starting point P 0 , assuming that the current discrete point is P t , the next discrete point is P t+1 , then is satisfied, the point coordinates at the discrete point are calculated by a numerical iteration method t+1 , and then P t+1 is taken as the current discrete point for a new round of iteration until P t+1 =P n After generating the line grid of the object surface edge, find the boundary of the main body that has not been discretized and generate a line grid according to the size requirement.

[0059] S52: generating a triangular surface grid on the main body using the front propagation method according to the line grid;

[0060] Specifically, the geometric information of all faces of the main body is traversed, and the lines contained in each face are found according to the topological information. The line meshes of each face are assembled into constraint boundaries, and then the triangular face meshes of each face are generated using the leading edge advancing method. The triangular face meshes on all the object faces are assembled into the initial leading edge surface, which is used for the generation of triangular prism elements.

[0061] S6: Based on the triangular mesh, generate anisotropic triangular prism elements on the main body;

[0062] S61: Input boundary layer parameters, take the triangular mesh on the main body surface as the growth surface, and calculate the normal and travel distance of each mesh point;

[0063] Specifically, the boundary layer parameters include the initial layer height, growth rate, and total number of layers; the normal of each grid point is the average normal of the surrounding triangular facets, and then the normal of the grid point is optimized using the Laplacian smoothing method; the travel distance calculated for each grid point is:

[0064]

[0065] here, This represents the current distance traveled. α The growth rate of the boundary layer, n This is the current floor number. h 0 This refers to the height of the first floor.

[0066] S62: Correct the normal vector of the grid points to obtain the corrected normal vector;

[0067] Specifically, assuming the number of grid points on the edge of the object surface is n, the set of coordinates of the grid points on any edge of the object surface is as follows: The set of grid point coordinates on its opposite side is Then the corrected normal vector at each point on the edge of the object surface is... for:

[0068]

[0069] By correcting the normal vectors of the grid points on the object surface, it can be ensured that the quadrilaterals on the internal dynamic and static interference surfaces of the generated boundary layer are structured units.

[0070] S63: Calculate the edge length based on the travel distance and the corrected normal vector, generate a layer of triangular prism elements, and use the top surface mesh of the triangular prism as a new growth surface;

[0071] Specifically, the length of the edge is calculated according to the distance and the corrected normal vector, a three-prism unit of a layer is generated in advance, and it is determined whether each three-prism unit has a mass or intersection problem, if the three-prism unit meets the requirements, the three-prism unit is retained, if the three-prism unit does not meet the requirements, the three-prism unit is deleted, and finally, a triangular surface mesh of the top layer is used as a new growth surface.

[0072] S64: It is determined whether the number of layers of the generated three-prism unit meets the requirements, if not, the whole process is iterated again, otherwise the generation of the three-prism unit is terminated.

[0073] Specifically, it is determined whether the number of layers of the currently generated three-prism unit is equal to the total number of layers in the boundary layer parameters, if yes, the generation of the new three-prism unit is stopped, otherwise the process of S61-S63 is repeated.

[0074] S7: According to the three-prism unit, triangular surface meshes and quadrilateral surface meshes are regenerated on the main body;

[0075] S71: According to the three-prism unit, triangular surface meshes of the object surface and the symmetry surface are regenerated;

[0076] Specifically, as shown in Figure 9 , the surface mesh of the symmetry surface destroyed by the boundary layer is regenerated, and the triangular surface mesh of the highest layer of the boundary layer is extracted as the new surface mesh of the object surface. The regenerated symmetry surface and object surface meshes will be used as the constraint boundary for the subsequent tetrahedral mesh generation.

[0077] S72: Line meshes of the object surface edge and the symmetry edge are regenerated;

[0078] Specifically, assuming that the number of grid points on the object surface edge is n , the coordinate set of the grid points on the object surface edge is , and the coordinate set of the reconstructed grid points is , the line mesh of the reconstructed object surface edge is:

[0079]

[0080] Here, h 0 is the height of the first layer, α is the growth rate of the boundary layer, n is the number of layers of the boundary layer, is the normal of the current point. As shown in Figure 10 , the symmetry edge is re-clipped according to the boundary layer, and the same number of grid points are arranged on the symmetry edge using the line discretization method of S51. The regenerated object surface edge and symmetry edge line meshes are assembled into a closed constraint boundary for generating quadrilateral surface meshes;

[0081] S73: generating quadrilateral surface mesh on the inner moving-static interference surface using the super limit mapping method according to the line mesh of the object surface edge and the symmetric edge.

[0082] Specifically, assuming that the number of line meshes of the upper and lower parts is N , the number of line meshes of the left and right parts is M , the line meshes of the 4 edges of the inner moving-static interference surface are mapped from the physical space (x, y) to the parameter space (u, v) e [0, 1] x [0, 1] , the line mesh of the upper object surface edge is represented as , the line mesh of the lower object surface edge is represented as , the line mesh of the left symmetric edge is represented as , and the line mesh of the right symmetric edge is represented as Discretize u and v as follows:

[0083]

[0084] Calculate the physical coordinates of the inner points through the super limit mapping formula:

[0085] + +(1- ) + -[(1- )(1- )r(0,0)

[0086] + (1- )r(N-1,0)+(1- ) r(0,M-1)+ r(N - 1, M - 1), i = 0, 1,... N - 1, j = 0, 1,...M-1

[0087] The quadrilateral surface mesh generated on the inner moving-static interference surface is shown in Figure 11 .

[0088] S8: generating quadrilateral surface mesh on the secondary body according to the quadrilateral surface mesh of the primary body;

[0089] S81: generating line mesh of the secondary body according to the quadrilateral surface mesh of the primary body;

[0090] Specifically, the entire process is as shown in Figure 12As shown, first, the object surface edge of the outer moving and static interference surface of the secondary body is discretized, and the same number of grid points is arranged on the object surface edge using the line discretization method of S51, wherein the number of grid points is consistent with the number of grid points of the object surface edge of the inner moving and static interference surface; in order to match the four-edge grid of the boundary layer of the inner moving and static interference surface of the main body, when discretizing the upper part and the lower part of the symmetric edge of the outer moving and static interference surface, the boundary layer parameters are used to discretize n points from the starting point and the ending point of the symmetric edge respectively, and the grid size is:

[0091] ,

[0092] Here, α is the growth rate of the boundary layer, i is the current point number, h 0 is the height of the first layer, and n is the number of boundary layer layers. Finally, the middle part of the symmetric edge of the outer moving and static interference surface is discretized, the points generated in the upper part and the lower part are used as new constraint endpoints, and the same number of grid points is arranged on the middle part of the symmetric edge using the line discretization method of S51. The line grid generated on the outer moving and static interference surface is assembled into a closed constraint boundary, which is used to generate a four-edge surface grid;

[0093] S82: generating a four-edge surface grid on the secondary body using the super limit mapping method according to the line grid of the secondary body.

[0094] Specifically, first, the surface grid of the inner moving and static interference surface of the main body is copied to the inner moving and static interference surface of the secondary body; then, the line grid on the outer moving and static interference surface is used as a constraint boundary, and the four-edge grid on the outer moving and static interference surface is generated by the super limit mapping method in S73. The surface grids on the inner moving and static interference surface and the outer moving and static interference surface will be used as constraint boundaries for generating hexahedral elements on the secondary body.

[0095] S9: generating hexahedral elements and pyramid elements on the secondary body according to the four-edge surface grid of the secondary body;

[0096] S91: generating hexahedral elements on the secondary body according to the four-edge surface grid of the secondary body in a same topological connection manner;

[0097] Specifically, the topology of the four-edge on the inner moving and static interference surface is consistent with the topology of the corresponding four-edge on the outer moving and static interference surface, and the same four-edge topology is connected together to form a hexahedral element, as shown in Figure 13 the 0176 four-edge on the inner moving and static interference surface and the 0176 four-edge on the outer moving and static interference surface form a new hexahedral element.

[0098] S92: generating a transition pyramid element on the hexahedral element.

[0099] Specifically, traverse all quadrilateral meshes, assuming that the quadrilateral vertex coordinates are v0, v1, v2, v3, first calculate the normal n and step h of the generated pyramid:

[0100] n=

[0101] h=

[0102] Take the center point of the quadrilateral C= , move a certain step along the normal n h to get the vertex a , then v0, v1, v2, v3, a The pyramid unit is composed; use the ray-triangle intersection detection to check whether the generated pyramid side surface intersects with other surfaces, if it intersects, adjust the step to half to regenerate the pyramid unit and perform intersection detection, if it does not intersect, complete the generation of the pyramid unit. The generated hexahedral unit and the pyramid unit are shown in Figure 14 , wherein the pyramid unit is mainly used as a transition unit of the structural hexahedron and the unstructured quadrilateral.

[0103] S10: generating a quadrilateral unit on the main body according to the pyramid unit;

[0104] S101: extracting the triangular surface mesh of the pyramid unit surface, and assembling it with the surface mesh of the re-generated symmetry surface and the object surface on the main body to form a closed surface mesh;

[0105] Specifically, as shown in Figure 15 , the surface mesh on the internal moving and static interference surface is replaced by the triangular surface mesh of the pyramid unit surface, and then assembled with the surface mesh of the re-generated symmetry surface and the object surface on the main body to obtain a closed triangular surface mesh;

[0106] S102: using the closed surface mesh as a constraint boundary, generating a quadrilateral unit inside using the Delaunay triangulation method;

[0107] Specifically, taking the closed surface triangular mesh as a geometric constraint, using the improved Bowyer-Watson algorithm to insert nodes inside the boundary and perform constrained Delaunay triangulation to generate an initial tetrahedral mesh; through geometric intersection detection, identify the tetrahedral units in conflict with the boundary, and perform splitting and merging operations to restore the boundary consistency; finally, apply the weighted Laplace smoothing algorithm to optimize the internal node distribution, thereby obtaining a tetrahedral mesh that strictly maintains the input geometric features and has excellent quality.

[0108] ​S103: merging the hexahedron element, the pyramid element, the tetrahedron element and the triangular prism element to generate a hybrid grid;

[0109] Specifically, the hexahedron element, the pyramid element, the tetrahedron element and the triangular prism element are merged to generate a hybrid grid, as shown in Figure 16 As shown, the total number of elements in the example is 1120170, of which the number of tetrahedron elements is 461560, the number of triangular prism elements is 656819, the number of pyramid elements is 720, and the number of hexahedron elements is 1071; Figure 17 For the volume grid of the flow field of the moving blade and the guide vane of the two-stage compressor, it can be seen that structured hexahedron elements are generated in the moving and static interference surface area, which helps to improve the accuracy and efficiency of data transmission, and realizes efficient and high-quality physical information transmission of multi-stage rotating machinery.

[0110] Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. The specification and examples given are exemplary only and the true scope and spirit of the application is indicated by the claims. The application is intended to cover any adaptations or variations of the application.

[0111] It should be understood that the application is not limited to the precise construction that has been described above and shown in the accompanying drawings, and that various modifications and changes can be made by those skilled in the art without departing from the scope of the application. The scope of the application is limited only by the appended claims.

Claims

1. A method for generating unstructured hybrid meshes for internal flow in rotating machinery that drives static interference surfaces, characterized in that, include: The geometry engine Open CASCADE is used to read the geometric model data of rotating machinery; Based on the geometric model data, assign boundary attributes to the geometric model; Based on the boundary properties of the geometric model, the geometric model is divided into a main body and a sub-body, and boundary properties are assigned to the main body and the sub-body. Based on the boundary properties of the main body and the sub-body, define symmetric edges and object surface edges; Based on the symmetry edge and the object surface edge, a triangular surface mesh is generated on the main body; Based on the triangular mesh, anisotropic triangular prism elements are generated on the main body; Based on the triangular prism unit, triangular and quadrilateral face meshes are regenerated on the main body; Based on the quadrilateral surface mesh of the main body, a quadrilateral surface mesh is generated on the sub-body; Based on the quadrilateral mesh of the sub-body, hexahedral elements and pyramidal elements are generated on the sub-body; Based on the pyramid unit, tetrahedral units are generated on the main body; Specifically, based on the boundary properties of the geometric model, the geometric model is divided into a main body and a sub-body, and boundary properties are assigned to the main body and the sub-body, including: Define a dividing surface based on the boundary properties of the geometric model, use Boolean operations to intersect the dividing surface with the geometric model, and return two divided geometric bodies, namely the main body and the sub-body; Mark the boundary attributes of the internal dynamic and static interference surface, object surface, and symmetry surface on the main body, and mark the boundary attributes of the internal dynamic and static interference surface, external dynamic and static interference surface, object surface, and symmetry surface on the sub-body; Specifically, based on the triangular mesh, anisotropic triangular prism elements are generated on the main body, including: Input boundary layer parameters, use the triangular mesh on the main body surface as the growth surface, and calculate the normal and travel distance of each mesh point; The corrected normal vector is obtained by correcting the normal vector of the grid points; The edge length is calculated based on the travel distance and the corrected normal vector, a layer of triangular prism elements is generated, and the top surface mesh of the triangular prism is used as a new growth surface. Determine if the number of layers of the generated triangular prism elements meets the requirements. If not, iterate the entire process again; otherwise, terminate the generation of triangular prism elements. Specifically, based on the triangular prism unit, triangular and quadrilateral face meshes are regenerated on the main body, including: Based on the triangular prism element, regenerate the triangular mesh of the object surface and the symmetry surface; Regenerate the line mesh for the object's surface edges and symmetric edges; Based on the line mesh of the object surface edges and symmetry edges, a quadrilateral surface mesh is generated on the internal dynamic-static interference surface using the overlimit mapping method.

2. The method according to claim 1, characterized in that, Based on the symmetry edge and the object surface edge, a triangular face mesh is generated on the main body, including: Arrange the same number of uniformly distributed grid points on the edge of the object surface of the main body to generate a line grid with an equal number of discrete segments, and then generate the line grid of the remaining boundary. Based on the line mesh, a triangular face mesh is generated on the body using a leading edge propulsion method.

3. The method according to claim 1, characterized in that, Based on the quadrilateral surface mesh of the main body, a quadrilateral surface mesh is generated on the sub-body, including: Based on the quadrilateral surface mesh of the main body, generate the line mesh of the sub-body; Based on the line mesh of the sub-body, a quadrilateral surface mesh is generated on the sub-body using the over-limit mapping method.

4. The method according to claim 1, characterized in that, Based on the quadrilateral mesh of the sub-body, hexahedral elements and pyramidal elements are generated on the sub-body, including: Based on the quadrilateral mesh of the sub-body, hexahedral elements are generated on the sub-body in the same topological connection manner; Transitional pyramid units are generated on the hexahedral units.

5. The method according to claim 1, characterized in that, Based on the pyramid unit, tetrahedral units are generated on the main body, including: Extract the triangular face mesh from the surface of the pyramid unit and assemble it with the face mesh of the symmetry plane and object surface regenerated on the main body to form a closed surface mesh; Using the closed surface mesh as a constraint boundary, tetrahedral elements are generated inside using the Delaunay triangulation method; The hexahedral, pyramidal, tetrahedral, and triangular prism elements are combined to generate a hybrid mesh.

Images