Surface mesh generation method and system based on recursive decomposition, and computer device

Abstract

The application discloses a curved surface grid generation method and system based on recursive decomposition, and a computer device. The method combines a direct method with a mapping method, and converts intersection judgment in a three-dimensional space in the direct method into operation in a two-dimensional space by using the mapping method. Therefore, a large amount of intersection calculation required can be effectively simplified, and required space data structure is more simple. Meanwhile, the method inherits the advantages of the direct method, such as convenient control of grid unit size and high surface grid quality. In addition, the method can realize fast generation of large-scale grids in parallel through the algorithm by combining the direct method with the mapping method.

Description

TECHNICAL FIELD

[0001] The present application relates to the grid generation technical field in the engineering calculation field such as computational fluid dynamics (CFD), and particularly relates to a curved surface grid generation method and system based on recursive decomposition, and a computer device. BACKGROUND

[0002] With the rapid development of computer technology, the CFD numerical simulation technology has become an important means of performance analysis in the process of aircraft aerodynamic shape design. Before using the CFD numerical simulation, a key preprocessing operation is to discretize the aircraft geometric model, that is, grid generation. The purpose of grid generation is to divide the given aircraft geometric model into a finite number of basic geometric units. Generally, a two-dimensional plane sheet or a three-dimensional curved surface sheet is divided into a triangular or quadrilateral element grid, and a three-dimensional geometric body is divided into a tetrahedral or hexahedral element grid. After the aircraft model is converted into a grid representation, the CFD method stores temperature, velocity and other physical quantities on each grid element, and then solves the physical interpretation (i.e., the physical quantity on each grid element) under a given working condition by using the physical conservation equation, and obtains the performance indicators such as the lift coefficient and the drag coefficient of the aircraft through related calculations. Therefore, the element size distribution and the element quality of the generated grid have a huge impact on the simulation results, thereby affecting the performance of the aircraft design scheme.

[0003] For the problem of aircraft aerodynamic performance evaluation, firstly, according to the designed aircraft CAD geometric model, a curved surface grid generation method is used to generate the curved surface grid corresponding to the model, and then different boundary conditions (such as inlet boundary incoming flow velocity, viscous boundary, slip boundary, free boundary, etc.) are set for different regions of the curved surface grid according to the given simulation working condition. Then, according to the generated curved surface grid, a three-dimensional body grid inside the space is further generated. Then, the curved surface grid, the boundary condition and the body grid are taken as the input of the CFD solver, and the CFD solver is iteratively solved until convergence, so that the physical quantity on each element of the curved surface grid and the body grid under the current working condition is obtained, and then the performance indicators such as the lift coefficient and the drag coefficient of the aircraft can be obtained through related calculation methods, thereby guiding the designers to adjust and optimize the shape of the aircraft.

[0004] Traditional curved surface grid generation methods have two ways of direct method and mapping method. In the process of generating grid, the direct method can directly control the size of the grid unit, and the final curved surface grid quality is high. But the disadvantage of the direct method is that in the process of grid generation, it will involve a lot of intersection judgment. Therefore, it is necessary to accurately and effectively determine the space condition, and the data structure design is more complex. Therefore, its calculation efficiency is low, and the implementation process is more complex. The biggest problem of the mapping method is that the ordinary mapping has no angle-preserving property. In the plane domain, the grid with good quality may become very poor after inverse mapping, which cannot be used as a numerical solution grid. In addition, whether the direct method or the mapping method, the general curved surface grid generation method is mostly based on the Delaunay triangulation method and the array surface advancing method. Among them, the Delaunay triangulation method needs to insert new nodes into the current grid one by one, and the array surface advancing method generates grid from the boundary to the interior of the region step by step. These two methods have strong sequential dependence, so it is difficult to realize large-scale grid generation quickly by parallel algorithm. In practical application, the efficiency of generating grid is slow when the aircraft geometric model is discretized and represented, so that the efficiency of obtaining performance indicators such as lift coefficient and drag coefficient of aircraft by numerical simulation calculation on a large amount of aircraft data is low. SUMMARY

[0005] The application provides a curved surface grid generation method and system based on recursive decomposition and a computer device, which are used to overcome the defects of low efficiency in obtaining performance indicators such as lift coefficient and drag coefficient of aircraft by numerical simulation calculation on a large amount of aircraft data in the prior art.

[0006] To achieve the above object, the application provides a curved surface grid generation method based on recursive decomposition, which comprises the following steps:

[0007] 101: Obtain geometric three-dimensional model data of a target object, and obtain topological information and geometric parameter information of the geometric three-dimensional model according to the geometric three-dimensional model data;

[0008] 102: Distribute grid nodes on the boundary curve of the geometric three-dimensional model by using a set grid node generation method according to the topological information and the geometric parameter information, and form initial grid units;

[0009] 103: Establish a local coordinate system of the initial grid units, and establish a mapping relationship function between the original three-dimensional coordinates and the projection two-dimensional coordinates according to the local coordinate system;

[0010] 104: Project the grid nodes on the initial grid units to a two-dimensional plane by using the mapping relationship in the form of overall mapping;

[0011] 105: connecting the projected non-adjacent grid nodes with a split line on the two-dimensional plane, and saving the split line completely located in the region according to the position relationship between the split line and the region surrounded by the grid nodes;

[0012] 106: optimizing the saved split line according to the angle influence, the length influence and the unit precision error, to obtain an optimal split line;

[0013] 107: pre-discretizing the optimal split line, projecting the pre-discretized nodes onto the curved surface of the geometric three-dimensional model through the mapping relationship function, and generating new grid nodes through iterative operation of the grid node generation mode to obtain a curved surface split line; the curved surface split line divides the initial grid unit into two sub-grid units;

[0014] 108: replacing the initial grid unit with the sub-grid unit, and iteratively performing steps 103-107 until the number of grid nodes contained in all the sub-grid units meets the set requirement, to obtain a curved surface grid.

[0015] To achieve the above object, the application further provides a curved surface grid generation system based on recursive decomposition, comprising:

[0016] an information acquisition module, configured to acquire geometric three-dimensional model data of a target object, and obtain topological information and geometric parameter information of the geometric three-dimensional model according to the geometric three-dimensional model data;

[0017] an initial grid unit generation module, configured to distribute grid nodes on a boundary curve of the geometric three-dimensional model according to the topological information and the geometric parameter information, and form an initial grid unit by using a set grid node generation mode;

[0018] a recursive generation module, configured to perform the following steps:

[0019] 103: establishing a local coordinate system of the initial grid unit, and establishing a mapping relationship function between the original three-dimensional coordinates and the projected two-dimensional coordinates according to the local coordinate system;

[0020] 104: projecting the grid nodes on the initial grid unit onto a two-dimensional plane in an integral mapping manner by using the mapping relationship;

[0021] 105: connecting the projected non-adjacent grid nodes with a split line on the two-dimensional plane, and saving the split line completely located in the region according to the position relationship between the split line and the region surrounded by the grid nodes;

[0022] 106: optimizing the saved split line according to the angle influence, the length influence and the unit precision error, to obtain an optimal split line;

[0023] 107: pre-discretizing the optimal segmentation line, projecting the pre-discretized nodes to the curved surface of the geometric three-dimensional model through the mapping relationship function, iteratively running the mesh node generation mode to generate new mesh nodes, and obtaining a curved surface segmentation line; the curved surface segmentation line divides the initial mesh element into two sub-mesh elements;

[0024] 108: replacing the initial mesh element with the sub-mesh element, iteratively running steps 103-107 until the number of mesh nodes contained in all the obtained sub-mesh elements meets the set requirement, and obtaining a curved surface mesh.

[0025] To achieve the above object, the application further provides a computer device, comprising a memory and a processor, the memory stores a computer program, and the processor implements the steps of the above method when executing the computer program.

[0026] To achieve the above object, the application further provides a computer readable storage medium, which stores a computer program, and the computer program implements the steps of the above method when executed by a processor.

[0027] Compared with the prior art, the application has the following beneficial effects:

[0028] The curved surface mesh generation method based on recursive decomposition provided by the application adopts a combination of direct method and mapping method, converts the intersection judgment in three-dimensional space in the direct method into operation in two-dimensional space by using the mapping method, so that the large amount of intersection calculation required can be effectively simplified, and the required space data structure is more concise. At the same time, the advantages of the direct method, such as easy control of mesh element size and surface mesh quality, are inherited. In addition, by combining the direct method and the mapping method, large-scale mesh can be quickly generated by algorithm parallelism, and the CFD numerical simulation efficiency is improved by the quick generation of large-scale mesh. In actual application, when a large amount of aircraft data is subjected to numerical simulation calculation to obtain performance indicators such as aircraft lift coefficient and drag coefficient, the calculation efficiency can be greatly improved. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description only constitute some embodiments of the application, and for those skilled in the art, other drawings can also be obtained from the structures shown in the drawings without creative labor.

[0030] Figure 1 The flowchart of the curved surface mesh generation method based on recursive decomposition provided by the application;

[0031] Figure 2 A schematic diagram illustrating the principle of the surface mesh generation method based on recursive decomposition provided by this invention;

[0032] Figure 3 This is a surface diagram of the target object in an embodiment of the present invention;

[0033] Figure 4 This is a surface mesh diagram generated by the surface mesh generation method for the target object in this embodiment of the invention.

[0034] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0036] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0037] This invention proposes a surface mesh generation method based on recursive decomposition, such as... Figure 1 and Figure 2 As shown, it includes the following steps:

[0038] 101: Obtain the geometric 3D model data of the target object, and obtain the topological information and geometric parameter information of the geometric 3D model based on the geometric 3D model data.

[0039] The target object can be an air wing, rocket, multi-port pipe, mechanical circuit board, etc. The aerodynamic shape data of the air wing is acquired, and performance simulation of the air wing's aerodynamic shape is performed based on this data to obtain the geometric representation data of the air wing's three-dimensional model. This geometric representation data includes geometric parameter information and topological information. The geometric parameter information includes the three-dimensional coordinates of vertices in the air wing's three-dimensional model, the B-spline representation of the three-dimensional curves, and the B-spline representation of the three-dimensional surfaces. The topological information includes the three-dimensional vertices corresponding to the upper endpoints of the three-dimensional curves and the three-dimensional curves corresponding to the boundary curves on the three-dimensional surfaces.

[0040] The 3D model data of the wing is stored using internationally recognized standard files, such as iges and step file formats.

[0041] 102: distributing grid nodes on the boundary curve of the geometric three-dimensional model according to the topological information and the geometric parameter information, using a set grid node generation method to form initial grid cells.

[0042] According to the three-dimensional coordinates of the vertices in the wing three-dimensional model, the B-spline representation of the three-dimensional curve, the B-spline representation of the three-dimensional surface, and the three-dimensional vertices corresponding to the end points of the three-dimensional curve and the three-dimensional curve corresponding to the boundary curve of the three-dimensional surface, grid nodes are distributed on the boundary curve of the wing three-dimensional model using a set grid node generation method to form initial grid cells.

[0043] 103: establishing a local coordinate system of the initial grid cells, and establishing a mapping relationship function between the original three-dimensional coordinates and the projected two-dimensional coordinates according to the local coordinate system.

[0044] 104: projecting the grid nodes on the initial grid cells to a two-dimensional plane using the mapping relationship in an overall mapping manner.

[0045] 105: connecting the projected non-adjacent grid nodes with a segmentation line on the two-dimensional plane, and saving the segmentation line completely located in the region according to the positional relationship of the segmentation line and the grid nodes surrounding the region.

[0046] Connecting the projected non-adjacent grid nodes with a segmentation line on the two-dimensional plane, and according to the positional relationship of the segmentation line and the grid nodes surrounding the region, the segmentation line can be divided into two cases: the line is completely located in the region and the line is not completely located outside the region. The segmentation line completely located in the region is a potential effective segmentation line, and the segmentation line is saved, otherwise it is invalid and discarded. When the surrounding region is a multi-connected region, the initial geometric region is preferentially divided into a single-connected region by connecting the inner and outer boundaries.

[0047] 106: optimizing the saved segmentation line according to the angle influence, the length influence, and the cell accuracy error to obtain an optimal segmentation line.

[0048] The saved segmentation line is optimized according to the angle error when the segmentation line is connected with the adjacent grid line, the length influence error of the segmentation line, and the grid cell error when the grid node generation method is adjusted in the discrete process of each segmentation line to obtain an optimal segmentation line.

[0049] 107: pre-discretizing the optimal segmentation line, projecting the pre-discretized nodes to the surface of the geometric three-dimensional model through the mapping relationship function, iteratively running the grid node generation method to generate new grid nodes, and obtaining a surface segmentation line; the surface segmentation line divides the initial grid cell into two sub-grid cells.

[0050] Projecting the pre-discretized nodes to the surface of the geometric three-dimensional model through the mapping relationship function can significantly reduce the mapping method error.

[0051] The grid node generation method is the same as the grid node generation method in step 102.

[0052] 108: Replace the initial mesh unit with a sub-mesh unit, iterate through steps 103 to 107 until the number of mesh nodes in all the obtained sub-mesh units meets the set requirements, and obtain the surface mesh.

[0053] The purpose of mesh generation is to divide the geometry of the target object into a finite number of basic geometric units. Generally, two-dimensional geometry is divided into a mesh of triangular or quadrilateral units. If it is divided into triangles, the termination condition for step 108 is that the number of mesh nodes is 3; if it is divided into quadrilaterals, the termination condition for step 108 is that the number of mesh nodes is 4.

[0054] Physical quantities are assigned to the mesh elements in the curved surface network, and the physical quantities are solved using the physical conservation equations to obtain the performance indicators of the wing; the physical quantities include the temperature and velocity of the wing; the performance indicators include the lift coefficient and the drag coefficient.

[0055] In one embodiment, the surface mesh generation example is as follows: the target object is a surface with a hole in the middle (e.g., Figure 3 As shown), this surface is described by an analytical expression, and after being generated by a mesh (as shown in the image), the surface is generated (as shown in the image). Figure 4 As shown, the mesh is discretized from several triangular elements. The nodes of the mesh are all on the original surface, but since triangles are planar, they don't necessarily fit perfectly onto the original surface. Therefore, this is a discrete approximation. Subsequent CFD calculations are performed on a unit basis: triangular elements or nodes. Flow field variables (such as velocity, pressure, and temperature at a given location) can be stored at the center of the triangular element or at the node. Therefore, the quality of the mesh elements and the node distribution have a significant impact on the results of subsequent calculations.

[0056] In the next embodiment, for step 101, the topology information includes surfaces and boundary curves represented by boundary representation, as well as the compositional relationship between curves and line endpoints; the geometric parameter information includes a single closed surface described by NURBS (Non-Uniform Rational B-Splines) and standard shape information of the boundary curves on the surface.

[0057] In another embodiment, step 102 specifically includes:

[0058] 201: Based on topological and geometric parameter information, the boundary curve of the target object is adaptively discretized into a series of points.

[0059] The specific way is as follows: there is a non-decreasing number set called node vector in the NURBS curve geometric parameter information. Removing the repeated elements in the set obtains a set U={u0, u1,..., u m} and generally u0=0, u m =1. Two elements a i , b i+1 are inserted between u i and u i to obtain a position set U'={u0, a0, b0, u1,..., u m-1 , a m-1 , b m-1 , u m} of the required serial discrete points on the curve, wherein a i =0.7×u i +0.3×u i+1 , b i =0.3×u i +0.7×u i+1 , and finally the elements in the position set are brought into the NURBS curve formula to calculate the three-dimensional position information of each point in the discrete point set;

[0060] 202: The length of the boundary curve is calculated by accumulating the distance lengths between the dense points in the point set;

[0061] 203: A global maximum grid cell size parameter is designed, and the number of segments of the boundary curve is calculated according to the global maximum grid cell size parameter;

[0062] 204: The segment spacing of the boundary curve is obtained according to the number of segments;

[0063] 205: The grid nodes are distributed on the boundary curve of the geometric three-dimensional model by using the coordinate interpolation method according to the segment spacing and the point set;

[0064] 206: The initial grid cells are formed according to the grid nodes.

[0065] In some embodiments, the number of segments of the boundary curve is calculated according to the global maximum grid cell size parameter, including,

[0066] The number of segments of the boundary curve is calculated according to the global maximum grid cell size parameter,

[0067]

[0068] In the formula, m represents the number of segments; l represents the length of the boundary curve; and size represents the global maximum grid cell size parameter.

[0069] In the next embodiment, the segment spacing of the boundary curve is obtained according to the segment number, including:

[0070] The segment spacing of the boundary curve is obtained according to the segment number, and the segment spacing s is calculated by the following formula:

[0071]

[0072] In the formula, s represents the segment spacing; m represents the segment number; and l represents the length of the boundary curve.

[0073] In another embodiment, for step 103, a local coordinate system of the initial mesh cell is established, and specifically:

[0074] Two points with the longest spacing are found in the mesh node, and the line connecting the two points is taken as the X axis of the local coordinate system;

[0075] The point farthest from the X axis is found in the mesh node, and the straight line passing through the farthest point and perpendicular to the X axis is taken as the Y axis of the local coordinate system.

[0076] In the next embodiment, step 106 is specifically:

[0077] According to the angle influence, the length influence, and the cell accuracy error, the error weight is calculated;

[0078] The segmentation line with the minimum error weight is selected as the optimal segmentation line of the current mesh cell.

[0079] In an embodiment, the error weight calculation formula is:

[0080] w = c1 × er0 + c2 × er1 + c3 × er2

[0081] In the formula, c1, c2, and c3 represent single weight coefficients, and according to experience, c1 = 0.5, c2 = 0.3, and c3 = 0.2; er0 represents the angle influence error; er1 represents the length influence error; and er2 represents the cell accuracy error.

[0082] (1) For the case of finally generating a triangular surface mesh.

[0083] The angle influence error er0: When the segmentation line is connected with the adjacent mesh line, four angles α i are formed inside the region, and the best case is that the angles are 60° and multiples thereof, and other cases are considered to have errors, which affect the quality of the subsequently generated triangular mesh cells. The angle influence error calculation formula is:

[0084]

[0085] Length influence error er1: each split line requires to be as short as possible, too long split line is easy to appear narrow area, which leads to local grid quality not ideal. Split line length is p, region outer boundary circumscribed circle diameter length is p0, then length influence error weight is

[0086] Unit precision error er2: in each split line discrete process, grid node generation method adjusts discrete node number to ensure that the number of grid nodes distributed on the split line is an integer. u0 is the ideal grid node number, u is the adjusted grid node number, then unit precision error weight is er2 = u0-u / u0.

[0087] (2) For the final generation of quadrilateral surface mesh.

[0088] Angle influence error er0: region inside forms 4 angles α i Angle meets 90° and its multiples for the best case. Angle influence error calculation formula is:

[0089] Length influence error er1 and unit precision error er2 are the same as the error of triangular surface mesh representation.

[0090] In the next embodiment, for step 107, the grid node generation method is iteratively run to generate new grid nodes, including:

[0091] 702: Calculate the length of all projected point lines by accumulating the distance between the points projected on the surface.

[0092] 703: Calculate the number of segments of all projected point lines according to the global maximum grid cell size parameter.

[0093] The global maximum grid cell size parameter is set in step 102.

[0094] 704: Obtain the segment spacing of all projected point lines according to the number of segments;

[0095] 705: Distribute grid nodes on all projected point lines using coordinate interpolation method according to segment spacing and point set;

[0096] 706: Form the split line of the surface according to the grid nodes.

[0097] After projecting the pre-discrete nodes onto the surface of the geometric three-dimensional model through the mapping relationship function, the distance of the projected points will change significantly. In order to reduce the error, it is necessary to generate new grid nodes by iteratively running the grid node generation method.

[0098] Since the length of all the connecting lines of the projection points is updated every time the grid node generation method is iterated, the grid node generation method needs to be iterated until the length of all the connecting lines of the projection points has no effect on the grid nodes in two consecutive times. The stopping iteration condition is length ratio t represents the length of all the connecting lines of the projection points in the current calculation, t0 represents the length of all the connecting lines of the projection points in the last calculation, and n represents the number of grid nodes for calculating the length of all the connecting lines of the projection points in the current calculation.

[0099] In one embodiment, the process of evaluating the aerodynamic performance of an aircraft according to the present application is as follows:

[0100] For the problem of evaluating the aerodynamic performance of an aircraft, after the curved surface grid of the aircraft is generated by the method of the present application, the curved surface grid needs to be divided into different regions according to the given calculation conditions (angle of attack, incoming flow speed, Reynolds number, etc.), and each region corresponds to different boundary conditions. For example, the boundary surface grid in the front part of the aircraft is set as an inlet boundary, the boundary surface grid in the rear part of the aircraft is set as an outlet boundary, the curved surface grid of the fuselage is set as a surface boundary, and the boundary surface grid far away from the fuselage is set as a far field boundary. Then, taking the curved surface grid as input, a volume grid generator is further used to generate a three-dimensional tetrahedral grid inside the space. Subsequently, taking the curved surface grid, the boundary conditions of each region, and the volume grid as input of a CFD solver, the CFD solver iteratively solves until it converges, and then the final physical quantity (temperature, speed, etc.) on each triangular element of the curved surface grid is obtained under the current working condition. Then, by performing integral operation on the physical quantity on the curved surface grid of the aircraft through a related calculation method, the lift coefficient, drag coefficient and other performance indicators of the aircraft can be obtained, thereby guiding the designers to adjust and optimize the shape of the aircraft. This process is the prior art, which comes from the article Numerical Simulation Method and Application of Aerodynamic Force and Aerodynamic Heat of Air-breathing Hypersonic Aircraft published by China Aerodynamic Research and Development Center.

[0101] The present application also proposes a curved surface grid generation system based on recursive decomposition, comprising:

[0102] An information acquisition module is configured to acquire geometric three-dimensional model data of a target object, and obtain topological information and geometric parameter information of the geometric three-dimensional model according to the geometric three-dimensional model data;

[0103] An initial grid element generation module is configured to distribute grid nodes on the boundary curves of the geometric three-dimensional model by using a set grid node generation method according to the topological information and the geometric parameter information, and form initial grid elements;

[0104] A recursive generation module is configured to perform the following steps:

[0105] 103: Establish a local coordinate system of the initial mesh unit, and establish a mapping relationship function between the original three-dimensional coordinates and the projected two-dimensional coordinates according to the local coordinate system;

[0106] 104: Project the grid nodes on the initial mesh unit to the two-dimensional plane by using the mapping relationship in an integral mapping manner;

[0107] 105: Connect the non-adjacent grid nodes after projection by using the segmentation line on the two-dimensional plane, and save the segmentation line completely located in the region according to the positional relationship of the segmentation line and the grid nodes surrounding the region;

[0108] 106: Optimize the saved segmentation line according to the angle influence, the length influence and the unit precision error to obtain the best segmentation line;

[0109] 107: Pre-disperse the best segmentation line, project the pre-dispersed nodes to the curved surface of the geometric three-dimensional model through the mapping relationship function, iteratively run the grid node generation mode to generate new grid nodes, and obtain the curved surface segmentation line; the curved surface segmentation line divides the initial mesh unit into two sub-mesh units;

[0110] 108: Replace the initial mesh unit with the sub-mesh unit, and iteratively run steps 103-107 until the number of grid nodes contained in all the obtained sub-mesh units meets the set requirement, and obtain the curved surface mesh.

[0111] The application also provides a computer device, including a memory and a processor, the memory stores a computer program, and the processor realizes the steps of the above method when executing the computer program.

[0112] The application also provides a computer readable storage medium, which stores a computer program, and the computer program realizes the steps of the above method when executed by a processor.

[0113] The above is only the preferred embodiment of the application, and does not limit the patent range of the application, and any equivalent structural transformation made according to the content of the application specification and drawings, or direct / indirect application in other related technical fields under the inventive concept of the application is included in the patent protection range of the application.

Claims

1. A method for generating a curved mesh based on recursive decomposition, characterized in that, The method comprises the following steps: 101: obtaining geometric three-dimensional model data of a target object, and obtaining topological information and geometric parameter information of a geometric three-dimensional model according to the geometric three-dimensional model data; 102: distributing mesh nodes on a boundary curve of the geometric three-dimensional model by using a set mesh node generation mode according to the topological information and the geometric parameter information, and forming an initial mesh element; 103: establishing a local coordinate system of the initial mesh element, and establishing a mapping relationship function between original three-dimensional coordinates and projection two-dimensional coordinates according to the local coordinate system; 104: projecting the mesh nodes on the initial mesh element to a two-dimensional plane by using the mapping relationship function in an overall mapping manner; 105: connecting the non-adjacent mesh nodes after projection by using a segmentation line on the two-dimensional plane, and saving the segmentation line completely located in a region according to the position relationship of the segmentation line and the mesh nodes; 106: optimizing the saved segmentation line according to angle influence, length influence and element accuracy error, and obtaining a best segmentation line; 107: pre-discretizing the best segmentation line, projecting the pre-discretized nodes to a curved surface of the geometric three-dimensional model by using the mapping relationship function, generating new mesh nodes by iteratively running the mesh node generation mode, and obtaining a curved surface segmentation line; the curved surface segmentation line divides the initial mesh element into two sub-mesh elements; 108: replacing the initial mesh element with the sub-mesh element, iteratively running steps 103-107 until the number of mesh nodes contained in all the sub-mesh elements meets a set requirement, and obtaining a curved surface mesh.

2. The curved mesh generation method of claim 1, wherein, The topological information comprises a curved surface and a boundary curve represented by a boundary representation method, and a composition relationship between the curved surface and a line end point; and the geometric parameter information comprises a single closed curved surface described by a NURBS and standard modeling information of a boundary curve on the curved surface.

3. The method of claim 2, wherein, The step 102 specifically comprises: adaptively discretizing the boundary curve of the target object into a serial point set according to the topological information and the geometric parameter information; calculating the length of the boundary curve by accumulating the distance length between dense points in the point set; designing a global maximum mesh element size parameter, and calculating the number of segments of the boundary curve according to the global maximum mesh element size parameter; obtaining a segment spacing of the boundary curve according to the number of segments; distributing mesh nodes on the boundary curve of the geometric three-dimensional model by using a coordinate interpolation mode according to the segment spacing and the point set; forming the initial mesh element according to the mesh nodes.

4. The method of claim 3, wherein, designing a global maximum mesh element size parameter, and calculating the number of segments of the boundary curve according to the global maximum mesh element size parameter, including, designing a global maximum mesh element size parameter, and calculating the number of segments of the boundary curve according to the global maximum mesh element size parameter, wherein m represents the number of segments, l represents the length of the boundary curve, and size represents the global maximum mesh element size parameter.

5. The method of claim 3, wherein, obtaining a segment spacing of the boundary curve according to the number of segments, including: obtaining a segment spacing of the boundary curve according to the number of segments, wherein s represents the segment spacing, m represents the number of segments, and l represents the length of the boundary curve.

6. The method of claim 1, wherein, In step 103, a local coordinate system of the initial mesh cell is established, specifically: Two points with the longest distance in the mesh node are found, and the line connecting the two points is the X-axis of the local coordinate system; The point farthest from the X-axis in the mesh node is found, and the straight line passing through the farthest point and perpendicular to the X-axis is the Y-axis of the local coordinate system.

7. The method of claim 1, wherein, Step 106 specifically includes: According to the angle influence, length influence and unit precision error, the error weight is calculated; The partition line with the minimum error weight is selected as the optimal partition line of the current mesh cell.

8. A recursive decomposition based curved mesh generation system, characterized by, It includes: An information acquisition module is configured to acquire geometric three-dimensional model data of a target object, and obtain topological information and geometric parameter information of the geometric three-dimensional model according to the geometric three-dimensional model data; An initial mesh cell generation module is configured to distribute mesh nodes on a boundary curve of the geometric three-dimensional model according to the topological information and the geometric parameter information, and form initial mesh cells by using a set mesh node generation mode; A recursive generation module is configured to perform the following steps: 103: Establish a local coordinate system of the initial mesh cell, and establish a mapping relationship function between the original three-dimensional coordinates and the projected two-dimensional coordinates according to the local coordinate system; 104: Project the mesh nodes on the initial mesh cell to a two-dimensional plane by using the mapping relationship function in an overall mapping manner; 105: Connect the non-adjacent mesh nodes after projection by using a partition line on the two-dimensional plane, and save the partition line completely located in the region according to the positional relationship between the partition line and the mesh nodes surrounding the region; 106: Optimize the saved partition line according to the angle influence, length influence and unit precision error to obtain an optimal partition line; 107: Pre-discretize the optimal partition line, project the pre-discretized nodes to the curved surface of the geometric three-dimensional model by using the mapping relationship function, generate new mesh nodes by using the mesh node generation mode, and obtain a curved surface partition line; the curved surface partition line divides the initial mesh cell into two sub-mesh cells; 108: Replace the initial mesh cell with the sub-mesh cells, and iterate steps 103-107 until the number of mesh nodes contained in all sub-mesh cells meets the set requirement, and obtain a curved surface mesh. 9.A computer device, comprising a memory and a processor, wherein the memory stores a computer program, and the computer device is configured to perform the method according to any one of claims 1-8 when the computer program is executed by the processor. The processor executes the computer program to realize the steps of the method in any one of claims 1-7.

10. A computer-readable storage medium having stored thereon a computer program, characterized in that, The computer program is executed by the processor to realize the steps of the method in any one of claims 1-7.

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