Grid generation method, device and equipment for aircraft airfoil quadrilateral structure finite element analysis and medium

Abstract

The invention discloses a grid generation method and device for finite element analysis of an aircraft airfoil quadrilateral structure, equipment and a medium, and relates to the technical field of multi-physics field coupling numerical simulation. Curve distances between discrete grid points and upper airfoil surface trailing edge points of an airfoil are calculated; the method comprises the following steps: initially segmenting an airfoil profile grid to obtain quadrilateral regions, calculating first control angular points at a front edge and a rear edge corresponding to an upper airfoil surface and a lower airfoil surface, second control angular points in an airfoil profile, first grid edges around an airfoil profile, intersecting edges at the front edge and the rear edge, and second grid edges in the airfoil profile, and constructing a computational domain grid; repeated grid point deletion, grid point list updating and grid unit list updating are carried out on the computational domain grid; and according to the target grid point list and the target grid unit list, generating a grid for finite element analysis of the quadrilateral structure of the aircraft airfoil, so that the full quadrangle of the grid units and the consistency of the grid units among different airfoil profiles can be ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of multi - physical - field coupling numerical simulation, and particularly relates to a method, device, equipment and medium for generating a grid for finite element analysis of an airfoil quadrilateral structure of an aircraft. Background Art

[0002] At present, there are mainly two methods for generating airfoil quadrilateral grids: one is to use an artificial interaction method, in which the airfoil is divided into multiple sub - regions, and then the quadrilateral grid is generated by splicing and meshing in each sub - region; the other is to use the method of boundary - layer advancement and tiling, in which grid points are arranged on the boundary contour of the airfoil, and then advanced along the inner - normal direction to generate a quadrilateral grid. However, the first method can ensure that the generated elements are all quadrilaterals, but it requires a large amount of manual intervention and is time - consuming; the second method can achieve automatic generation, but there are conflicting regions in the advancing direction, and the quadrilateral grid may degenerate into a triangle, unable to ensure all - quadrilateralization, and the grids of different airfoil profiles may face the situation of inconsistent numbers of nodes, elements and node connection relationships, resulting in the difficulty of forming hexahedral elements.

[0003] As can be seen from the above, how to ensure the all - quadrilateralization of grid elements and the consistency of grid elements between different airfoil profiles to realize the grid generation for finite element analysis of the airfoil quadrilateral structure of an aircraft is a problem to be solved in this field. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a method, device, equipment and medium for generating a grid for finite element analysis of an airfoil quadrilateral structure of an aircraft, which can ensure the all - quadrilateralization of grid elements and the consistency of grid elements between different airfoil profiles, and realize the grid generation for finite element analysis of the airfoil quadrilateral structure of an aircraft. The specific scheme is as follows:

[0005] In the first aspect, the present application discloses a method for generating a grid for finite element analysis of an airfoil quadrilateral structure of an aircraft, including:

[0006] Obtaining the number and coordinate data of discrete grid points for describing the geometric shape of the airfoil of the aircraft, and calculating the curve distance between the discrete grid points and the trailing - edge point of the upper surface of the airfoil based on the number and the coordinate data;

[0007] Using the curve distance to establish a geometric parameterization model of the airfoil, initially dividing the airfoil grid to obtain each quadrilateral region, and calculating the first control corner points at the leading edge and trailing edge corresponding to the upper surface and the lower surface respectively based on the geometric parameterization model of the airfoil, the coordinate data and the curve distance;

[0008] Generate each second control corner point inside the airfoil based on each of the first control corner points, and generate each first grid edge around the airfoil profile using each of the first control corner points and each of the second control corner points;

[0009] Generate each intersecting edge at the leading edge and the trailing edge according to each of the first grid edges, generate the second grid edges inside the airfoil using each of the second control corner points, and generate the target quadrilateral region based on each of the quadrilateral regions, each of the first grid edges, each of the intersecting edges, and each of the second grid edges;

[0010] Generate a quadrilateral grid using the target quadrilateral region, construct a computational domain grid based on the quadrilateral grid, and perform operations of repeated grid point deletion, grid point list update, and grid cell list update on the computational domain grid to obtain a target grid point list and a target grid cell list;

[0011] Generate a grid for finite element analysis of the quadrilateral structure of the aircraft airfoil according to the target grid point list and the target grid cell list.

[0012] Optionally, the obtaining the number and coordinate data of the discrete grid points for describing the geometric shape of the aircraft airfoil, and calculating the curve distance between the discrete grid points and the trailing edge point of the upper surface of the airfoil based on the number and the coordinate data, includes:

[0013] Obtain the number and coordinate data of the discrete grid points from a preset data file or formula for describing the geometric shape of the airfoil;

[0014] Determine the trailing edge point of the upper surface of the airfoil, and calculate the curve distance between the discrete grid points and the trailing edge point of the upper surface of the airfoil based on the number and the coordinate data using a curve distance calculation formula; the curve distance calculation formula is:

[0015] ;

[0016] ;

[0017] Wherein, is the curve distance of the i-th discrete grid point, is the curve distance of the (i - 1)-th discrete grid point, n is the number of discrete grid points, is the straight-line distance between the (i - 1)-th discrete grid point and the i-th discrete grid point, is the coordinate data of the i-th discrete grid point, is the coordinate data of the (i - 1)-th discrete grid point.

[0018] Optionally, the establishing an airfoil geometric parameterization model using the curve distance includes:

[0019] A geometric parameterization model of an airfoil is established by using the curve distance and adopting a one-dimensional radial basis interpolation method; the expression of the geometric parameterization model of the airfoil is as follows:

[0020] ;

[0021] where f is the interpolation function, n is the number of discrete grid points, is the curve distance, is the interpolation coefficient, is the basis function, and d is the interpolation variable.

[0022] Optionally, calculating the first control corner points corresponding to the leading edge and the trailing edge of the upper airfoil surface and the lower airfoil surface respectively based on the airfoil geometric parameterization model, the coordinate data, and the curve distance includes:

[0023] Determining the first control corner points at the trailing edge of the upper airfoil surface and the first control corner points at the trailing edge of the lower airfoil surface of the airfoil based on the coordinate data;

[0024] Performing plane coordinate calculation on the coordinate data, the preset trailing edge control corner point range, and the curve distance by using the airfoil geometric parameterization model to obtain the first control corner points within the preset trailing edge control corner point range of the upper airfoil surface and the first control corner points within the preset trailing edge control corner point range of the lower airfoil surface;

[0025] Performing iterative calculation on the curve distance based on the bisection method to obtain the leading edge control corner point range, and performing plane coordinate calculation on the coordinate data, the leading edge control corner point range, and the curve distance by using the airfoil geometric parameterization model to obtain the first control corner points within the leading edge control corner point range of the upper airfoil surface and the first control corner points within the leading edge control corner point range of the lower airfoil surface.

[0026] Optionally, generating the second control corner points inside the airfoil based on each of the first control corner points includes:

[0027] Advancing each of the first control corner points along the inner normal direction of the airfoil, the airfoil tangent direction, and the angular bisector direction of the line connecting the control corner points to generate the second control corner points inside the airfoil.

[0028] Optionally, generating a quadrilateral mesh by using the target quadrilateral region includes:

[0029] Obtaining the target quadrilateral region assembly information during the process of generating the target quadrilateral region;

[0030] Generating a quadrilateral mesh by using a two-dimensional transfinite interpolation method and based on the target quadrilateral region assembly information.

[0031] Optionally, constructing a computational domain grid based on the quadrilateral grid, and performing operations of deleting duplicate grid points, updating the grid point list, and updating the grid cell list on the computational domain grid to obtain a target grid point list and a target grid cell list, including:

[0032] Constructing a computational domain grid including a grid point list and a grid cell list in an unstructured manner defined based on the quadrilateral grid and using a node list and a cell list;

[0033] Deleting duplicate grid points in the grid point list of the computational domain grid, and performing an update operation on the grid point list to obtain a target grid point list;

[0034] Performing an update operation on the grid cell list according to the mapping relationship between the original grid point numbers and the updated grid point numbers to obtain a target grid cell list.

[0035] In a second aspect, the present application discloses a grid generation device for finite element analysis of an airfoil quadrilateral structure of an aircraft, including:

[0036] A curve distance calculation module, configured to obtain the number and coordinate data of discrete grid points for describing the geometric shape of the airfoil of the aircraft, and calculate the curve distance between the discrete grid points and the trailing edge point of the upper surface of the airfoil based on the number and the coordinate data;

[0037] A first control corner point calculation module, configured to use the curve distance to establish an airfoil geometric parameterization model, perform an initial segmentation on the airfoil grid to obtain each quadrilateral region, and calculate each first control corner point at the leading edge and the trailing edge corresponding to the upper surface and the lower surface respectively based on the airfoil geometric parameterization model, the coordinate data, and the curve distance;

[0038] A first grid edge generation module, configured to generate each second control corner point inside the airfoil based on each of the first control corner points, and generate each first grid edge around the airfoil contour by using each of the first control corner points and each of the second control corner points;

[0039] A target quadrilateral region generation module, configured to generate each intersection edge at the leading edge and the trailing edge according to each of the first grid edges, generate second grid edges inside the airfoil by using each of the second control corner points, and generate a target quadrilateral region based on each of the quadrilateral regions, each of the first grid edges, each of the intersection edges, and each of the second grid edges;

[0040] An update module, configured to generate a quadrilateral grid by using the target quadrilateral region, construct a computational domain grid based on the quadrilateral grid, and perform operations of deleting duplicate grid points, updating the grid point list, and updating the grid cell list on the computational domain grid to obtain a target grid point list and a target grid cell list;

[0041] A mesh generation module, configured to generate a mesh for finite element analysis of an aircraft airfoil quadrilateral structure according to the list of target mesh points and the list of target mesh elements.

[0042] In a third aspect, the present application discloses an electronic device, including:

[0043] A memory, configured to store a computer program;

[0044] A processor, configured to execute the computer program to implement the foregoing mesh generation method for finite element analysis of an aircraft airfoil quadrilateral structure.

[0045] In a fourth aspect, the present application discloses a computer storage medium, configured to store a computer program; wherein, when the computer program is executed by a processor, the steps of the foregoing disclosed mesh generation method for finite element analysis of an aircraft airfoil quadrilateral structure are implemented.

[0046] It can be seen that the present application provides a method for generating a mesh for finite element analysis of a quadrilateral structure of an aircraft airfoil, including obtaining the number and coordinate data of discrete mesh points for describing the geometric shape of the aircraft airfoil, calculating the curve distance between the discrete mesh points and the trailing edge point of the upper airfoil surface based on the number and the coordinate data; establishing a geometric parameterization model of the airfoil by using the curve distance, initially dividing the airfoil mesh to obtain each quadrilateral region, calculating each first control corner point at the leading edge and the trailing edge corresponding to the upper airfoil surface and the lower airfoil surface respectively based on the geometric parameterization model of the airfoil, the coordinate data and the curve distance; generating each second control corner point inside the airfoil based on each of the first control corner points, generating each first mesh edge around the airfoil contour by using each of the first control corner points and each of the second control corner points; generating each intersecting edge at the leading edge and the trailing edge according to each of the first mesh edges, generating the second mesh edge inside the airfoil by using each of the second control corner points, generating a target quadrilateral region based on each of the quadrilateral regions, each of the first mesh edges, each of the intersecting edges and each of the second mesh edges; generating a quadrilateral mesh by using the target quadrilateral region, constructing a computational domain mesh based on the quadrilateral mesh, performing repeated mesh point deletion operations, mesh point list update operations and mesh cell list update operations on the computational domain mesh to obtain a target mesh point list and a target mesh cell list; generating a mesh for finite element analysis of the quadrilateral structure of the aircraft airfoil according to the target mesh point list and the target mesh cell list. The present application calculates the curve distance between the discrete mesh points and the trailing edge point of the upper airfoil surface based on the number and coordinate data of the discrete mesh points for describing the geometric shape of the aircraft airfoil, can accurately describe the geometric shape of the airfoil, establish a geometric parameterization model of the airfoil, initially divide the airfoil mesh to obtain each quadrilateral region, calculate each first control corner point at the leading edge and the trailing edge corresponding to the upper airfoil surface and the lower airfoil surface respectively, generate each second control corner point inside the airfoil, generate each first mesh edge around the airfoil contour by using each of the first control corner points and each of the second control corner points, generate each intersecting edge at the leading edge and the trailing edge according to each of the first mesh edges, generate the second mesh edge inside the airfoil by using each of the second control corner points, generate a target quadrilateral region, generate a quadrilateral mesh by using the target quadrilateral region, realize the generation of the quadrilateral mesh for each target quadrilateral region, and then assemble it into an overall quadrilateral mesh, construct a computational domain mesh, perform repeated mesh point deletion operations, mesh point list update operations and mesh cell list update operations on the computational domain mesh to obtain a target mesh point list and a target mesh cell list, and generate a mesh for finite element analysis of the quadrilateral structure of the aircraft airfoil, ensuring the full quadrilateralization of the mesh cells and the consistency of the mesh cells between different airfoil profiles, and realizing the generation of the mesh for finite element analysis of the quadrilateral structure of the aircraft airfoil. Description of the Drawings

[0047] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to the provided drawings.

[0048] Figure 1 Flowchart of a grid generation method for finite element analysis of a quadrilateral structure of an aircraft airfoil disclosed in this application;

[0049] Figure 2 Diagram for describing the position of an airfoil disclosed in this application;

[0050] Figure 3 Example diagram of area division disclosed in this application;

[0051] Figure 4 Example diagram of a control corner point disclosed in this application;

[0052] Figure 5 Example diagram of a grid edge disclosed in this application;

[0053] Figure 6 Assembled quadrilateral grid diagram of partitioned areas disclosed in this application;

[0054] Figure 7 Quadrilateral grid diagram of a unified computational domain disclosed in this application;

[0055] Figure 8 Schematic diagram of the structure of a grid generation device for finite element analysis of a quadrilateral structure of an aircraft airfoil disclosed in this application;

[0056] Figure 9 Structural diagram of an electronic device provided by this application.

[0057] The reference signs in the drawings are as follows:

[0058] 1 - trailing edge, 2 - upper wing surface, 3 - leading edge, 4 - lower wing surface, 5 - airfoil profile, 6 - quadrilateral region one, 7 - quadrilateral region two, 8 - quadrilateral region three, 9 - quadrilateral region four, 10 - quadrilateral region five, 11 - quadrilateral region six, 12 - control corner point one, 13 - control corner point two, 14 - control corner point three, 15 - control corner point four, 16 - control corner point five, 17 - control corner point six, 18 - control corner point seven, 19 - control corner point eight, 20 - control corner point nine, 21 - control corner point ten, 22 - grid edge one, 23 - grid edge two, 24 - grid edge three, 25 - grid edge four, 26 - grid edge five, 27 - grid edge six, 28 - grid edge seven, 29 - grid edge eight, 30 - grid edge nine, 31 - grid edge ten, 32 - grid edge eleven, 33 - grid edge twelve, 34 - grid edge thirteen, 35 - grid edge fourteen, 36 - grid edge fifteen. Detailed implementation manner

[0059] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0060] Currently, there are mainly two methods for generating airfoil quadrilateral meshes: one is to use the method of manual interaction. By dividing the airfoil into multiple sub - regions, and then splicing and dividing in each sub - region to generate quadrilateral meshes; the other is to adopt the method of boundary - layer advancement and tiling. Grid points are arranged on the boundary contour of the airfoil, and then advanced along the direction of the inner normal to generate quadrilateral meshes. However, the first method can ensure that the generated elements are all quadrilaterals, but it requires a large amount of manual intervention and is time - consuming; the second method can achieve automatic generation, but there are conflicting regions in the advancement direction, and the quadrilateral meshes may degenerate into triangles, unable to ensure all - quadrilateralization. Moreover, for different airfoil profiles, the number of nodes, the number of elements, and the node connection relationships may be inconsistent, resulting in the difficulty of forming hexahedral elements. As can be seen from the above, how to ensure the all - quadrilateralization of grid elements and the consistency of grid elements between different airfoil profiles, and realize the grid generation for the finite - element analysis of the airfoil quadrilateral structure of the aircraft is a problem to be solved in the art.

[0061] See Figure 1 As shown, the embodiments of the present invention disclose a method for generating a grid for the finite - element analysis of the airfoil quadrilateral structure of an aircraft, which may specifically include:

[0062] Step S11: Obtain the number and coordinate data of discrete grid points for describing the geometric shape of the aircraft airfoil, and calculate the curve distance between the discrete grid points and the trailing edge point of the upper surface of the airfoil based on the number and the coordinate data.

[0063] In this embodiment, obtain the number and coordinate data of discrete grid points from a preset data file or formula for describing the airfoil geometry; determine the trailing edge point of the upper surface of the airfoil, and calculate the curve distance between the discrete grid points and the trailing edge point of the upper surface of the airfoil based on the number and the coordinate data by using a curve distance calculation formula; the curve distance calculation formula is:

[0064] ;

[0065] ;

[0066] where, is the curve distance of the i-th discrete grid point, is the curve distance of the (i - 1)-th discrete grid point, n is the number of discrete grid points, is the straight-line distance between the (i - 1)-th discrete grid point and the i-th discrete grid point, is the coordinate data of the i-th discrete grid point, is the coordinate data of the (i - 1)-th discrete grid point.

[0067] Specifically, if the discrete point coordinates for describing the airfoil geometry are recorded in a data file, according to the file name, first read the number n of airfoil discrete grid points, and then sequentially read in the coordinate data of the discrete grid points . For the convenience of parameterization implementation in subsequent steps, the starting position of the discrete grid points starts from the trailing edge point of the upper surface of the airfoil and traverses counterclockwise to the trailing edge point of the lower surface. The data with inconsistent starting positions and arrangement directions can be adjusted to meet the requirements through a simple sorting algorithm; if the airfoil geometry is described by a formula, define the number n of discrete points, and then start from the trailing edge point of the upper surface of the airfoil and sequentially generate all the coordinate data of the discrete grid points for describing the airfoil geometry along the counterclockwise direction . For example, if the number of discrete points is 201, first read the number 201 of airfoil discrete grid points, and then sequentially read in the coordinate data of the discrete grid points .

[0068] In this embodiment, the airfoil position description is as Figure 2 shown. Number 1 is the trailing edge of the airfoil, number 2 is the upper surface of the airfoil, number 3 is the leading edge of the airfoil, number 4 is the lower surface of the airfoil, number 5 is the airfoil profile, and calculate the curve distance Starting from the trailing edge point of the upper airfoil surface, the curvilinear distance from each discrete grid point to the trailing edge point of the upper airfoil surface is calculated point by point. When the discrete grid points are dense enough, the airfoil geometry can be described more accurately.

[0069] Step S12: Establish an airfoil geometric parameterization model using the curvilinear distance, perform an initial segmentation on the airfoil grid to obtain each quadrilateral region, and calculate the first control corner points at the leading edge and trailing edge corresponding to the upper airfoil surface and the lower airfoil surface respectively based on the airfoil geometric parameterization model, the coordinate data, and the curvilinear distance.

[0070] In this embodiment, an airfoil geometric parameterization model is established using the curvilinear distance and the one-dimensional radial basis interpolation method; the expression of the airfoil geometric parameterization model is:

[0071] ;

[0072] where f is the interpolation function, n is the number of discrete grid points, is the curvilinear distance, is the interpolation coefficient, is the basis function, and d is the interpolation variable.

[0073] Given the coordinate values at the positions of n values on the airfoil, an airfoil geometric parameterization model can be established through one-dimensional interpolation; there are various methods for one-dimensional interpolation, such as polynomial, Lagrange, spline, etc. The expression of the airfoil geometric parameterization model established by the one-dimensional radial basis interpolation method in the present invention is as shown above, where is the interpolation coefficient, which is determined by the coordinate values at the positions of the known n values, and the coefficients and of x and y are calculated respectively by the following formulas:

[0074] ;

[0075] ;

[0076] ;

[0077] ;

[0078] where , and the basis function can select different types. In the present invention, the compactly supported basis function Wendland’s C2 is selected;

[0079] If represents the curvilinear distance of 201 known points, then , They are calculated respectively by the following formulas:

[0080] ;

[0081] ;

[0082] ;

[0083] .

[0084] Then, the airfoil grid is initially segmented to obtain each quadrilateral region, and the first control corner point at the trailing edge of the upper airfoil surface and the first control corner point at the trailing edge of the lower airfoil surface of the airfoil are determined based on the coordinate data; the airfoil geometric parameterization model is used to perform planar coordinate calculations on the coordinate data, the preset trailing edge control corner point range, and the curve distance to obtain the first control corner points within the preset trailing edge control corner point range of the upper airfoil surface and the first control corner points within the preset trailing edge control corner point range of the lower airfoil surface; the curve distance is iteratively calculated based on the bisection method to obtain the leading edge control corner point range, and the airfoil geometric parameterization model is used to perform planar coordinate calculations on the coordinate data, the leading edge control corner point range, and the curve distance to obtain the first control corner points within the leading edge control corner point range of the upper airfoil surface and the first control corner points within the leading edge control corner point range of the lower airfoil surface.

[0085] The specific initial segmentation process is as follows: To more conveniently control the distribution of airfoil grid cells, the entire airfoil is segmented into six quadrilateral regions. One quadrilateral region is divided near the trailing edge, and the remaining part is divided into five quadrilateral regions. One region is located in the middle, and four quadrilateral regions surround the middle quadrilateral region. The six quadrilateral regions have a total of 10 control corner points and 15 edges. Among the 10 control corner points, 6 are located on the airfoil, and 4 corner points are located inside the airfoil. Among the 15 edges, 6 are located on the airfoil, 5 edges intersect with the airfoil, and 4 edges are located inside the airfoil.

[0086] For example, the example of region segmentation is as shown in Figure 3 where the numbers 6 - 11 are the six divided quadrilateral regions, namely quadrilateral region one 6, quadrilateral region two 7, quadrilateral region three 8, quadrilateral region four 9, quadrilateral region five 10, and quadrilateral region six 11. One quadrilateral region is divided near the trailing edge, and the remaining part is divided into five quadrilateral regions. One region is located in the middle, and four quadrilateral regions surround the middle quadrilateral region. The six quadrilateral regions have a total of 10 control corner points and 15 edges. Among the 10 control corner points, 6 are located on the airfoil, and 4 corner points are located inside the airfoil. Among the 15 edges, 6 are located on the airfoil, 5 edges intersect with the airfoil, and 4 edges are located inside the airfoil.

[0087] In this embodiment, the example of the control corner point is as shown inFigure 4 As shown in the figure, there are control corner point 12, control corner point 13, control corner point 14, control corner point 15, control corner point 16, control corner point 17, control corner point 18, control corner point 19, control corner point 20, and control corner point 21. Control corner point 12 and control corner point 17 are two control corner points at the trailing edge. Control corner point 13 and control corner point 16 are two control corner points near the trailing edges of the upper and lower wing surfaces. Control corner point 14 and control corner point 15 are two control corner points near the leading edges of the upper and lower wing surfaces. These six corner points form 6 control corner points on the airfoil. The process of determining the first control corner point at the trailing edge of the upper wing surface and the first control corner point at the trailing edge of the lower wing surface is as follows: Control corner point 12 at the trailing edge position of the upper wing surface and control corner point 17 at the trailing edge position of the lower wing surface respectively take the coordinates of the points at the trailing edge positions of the upper and lower wing surfaces of the airfoil, that is, the first point and the last point describing the geometric shape of the airfoil, so there is , .

[0088] The process of determining the first control corner point within the preset trailing edge control corner point range of the upper wing surface and the first control corner point within the preset trailing edge control corner point range of the lower wing surface is as follows: The two control corner points near the trailing edges of the upper and lower wing surfaces are used to adjust the airfoil grid distribution and improve the orthogonality of the grid elements. For example, when the two control corner points near the trailing edges of the upper and lower wing surfaces are respectively located at about 0.12c from the trailing edge position (the preset trailing edge control corner point range is 0.12c), the quality of the generated airfoil quadrilateral element grid is better, where c is the chord length of the airfoil. That is, the curve distance d of control corner point 13 near the trailing edge of the upper wing surface is 0.12c, and the curve distance d of control corner point 16 near the trailing edge of the lower wing surface is , where is the curve distance from the last of the 201 discrete points describing the airfoil to the trailing edge position of the upper wing surface, and has a value of 2.04c. So the curve distance d of control corner point 16 is 1.92. Substituting into the expressions of the airfoil geometric parameterization model and combining with the four formulas at , , the planar coordinates , of control corner point 13 and control corner point 16 are:

[0089] ;

[0090] .

[0091] The process for determining the first control corner point within the leading-edge control corner point range of the upper airfoil surface and the first control corner point within the leading-edge control corner point range of the lower airfoil surface is as follows: The two control corner points near the leading edges of the upper and lower airfoil surfaces are for constructing an internal O-shaped topology to eliminate the problem of poor element quality when directly generating quadrilateral meshes. For example, when the two control corner points near the leading edges of the upper and lower airfoil surfaces are respectively located at a position 0.03c away from the leading edge (the leading-edge control corner point range is 0.03c), the quality control of the quadrilateral elements is better. First, calculate the curvilinear distance 1.03c from the leading-edge position point to the trailing-edge point of the upper airfoil surface. The specific calculation process is given in the subsequent steps. The curvilinear distance d of the control corner point near the leading edge of the upper airfoil surface is 1.03c - 0.03c = 1.00c, and the curvilinear distance d of the control corner point near the leading edge of the lower airfoil surface is 1.03c + 0.03c = 1.06c. The leading-edge point of the airfoil is not directly given and cannot be directly calculated from the geometric discrete point data. The present invention assumes that the point where y = 0 near the leading-edge point is the leading-edge point, and then obtains the curvilinear distance of the leading-edge point through bisection iteration. The specific iteration process is as follows:

[0092] (1) Define one point on each of the upper and lower airfoil surfaces near the leading-edge point of the airfoil. Their curvilinear distances from the trailing-edge point of the upper airfoil surface are respectively and , and set and to initial values of 0.8c and 1.2c respectively.

[0093] (2) Based on , use the expression of the airfoil geometric parameterization model to calculate the y-coordinate of the point on the upper airfoil surface. If is less than 0, then , and recalculate and judge until is greater than 0.

[0094] (3) Based on <o000275>, use the expression of the airfoil geometric parameterization model to calculate the y-coordinate of the point on the lower airfoil surface. If is greater than 0, then , and recalculate and judge until is greater than 0.

[0095] (4) Define the midpoint of the curve , and use the expression of the airfoil geometric parameterization model to calculate the y-coordinate at the position of .

[0096] (5) If , then ; , then It should be noted that there may be some tags that seem to be misformatted in the original text (such as <o000275> which might be ). The translation is done based on the best understanding of the provided content., jump to step (4) and repeat the execution, where is an extremely small positive number, and the present invention defines .

[0097] (6) , the process ends.

[0098] Then, the coordinates of control point three near the leading edge of the upper airfoil can be calculated by the following formula:

[0099] ;

[0100] Similarly, the coordinates of control point four near the leading edge of the upper airfoil can be calculated by the following formula:

[0101] ;

[0102] where is the curve distance of the leading edge of the upper airfoil.

[0103] Step S13: Generate each second control point inside the airfoil based on each of the first control points, and generate each first grid edge around the airfoil profile using each of the first control points and each of the second control points.

[0104] In this embodiment, each of the first control points is advanced along the inner normal direction of the airfoil, the tangential direction of the airfoil, and the angular bisector direction of the line connecting the control points to generate each second control point inside the airfoil, and each first grid edge around the airfoil profile is generated using each of the first control points and each of the second control points.

[0105] Specifically, as Figure 4 shown, control point seven 18 and control point ten 21 are obtained by advancing two control points near the upper and lower trailing edges of the airfoil inward, and control point eight 19 and control point nine 20 are obtained by advancing two control points near the upper and lower leading edges of the airfoil inward. The four control points inside the airfoil are obtained by advancing control points two 13, three 14, four 15, and five 16 on the airfoil inward. Among them, the inner control points eight 19 and nine 20 near the leading edge of the airfoil are obtained by advancing control points three 14 and four 15 along the inner normal direction of the airfoil, and the inner control points seven 18 and ten 21 near the trailing edge of the airfoil are obtained by advancing control points two 13 and five 16 along the tangential direction of the airfoil and the angular bisector of the line connecting control points two 13 and five 16.

[0106] The tangent of the position of the control point on the airfoil surface is approximately calculated in the following way. According to the curve distance d of the control point, deviate forward and backward by , i.e., the curve distance of the tangent starting point , the curve distance of the tangent end point . Among them, is a very small curve distance deviation. In the present invention, = 0.001c is selected. The coordinates of the tangent starting point and the end point can be obtained by using the expression of the airfoil geometric parameterization model , . Then, the unit tangent vector for controlling the corner point position can be expressed as:

[0107] ;

[0108] Among them, and are the components of the unit tangent vector in the horizontal axis direction and the vertical axis direction.

[0109] The unit normal vector can be obtained from the unit tangent vector for controlling the corner point position of the airfoil as:

[0110] ;

[0111] Among them, and are the components of the tangent of the coordinate (x, y) on the airfoil curve in the horizontal axis direction and the vertical axis direction.

[0112] For example, if the internal propulsion distance is selected as 0.015c, better grid cell quality can be obtained. Therefore, the coordinates of control corner point eight and control corner point nine can be expressed as:

[0113] ;

[0114] ;

[0115] Among them, and are the components of the tangent of control corner point three in the x direction and the y direction, and are the components of the tangent of control corner point four in the x direction and the y direction.

[0116] The specific value is determined according to the thickness value of the airfoil. The greater the thickness, the longer the propulsion distance that can be selected. The unit vector of the line connecting control corner point two and control corner point five can be expressed as:

[0117] ;

[0118] Among them, and are the components of the unit vector in the horizontal axis direction and the vertical axis direction.

[0119] The advancing directions of control corner point 2 and control corner point 5 into the airfoil are along the angle bisector of the airfoil tangent and the line connecting control corner point 2 and control corner point 5. The advancing direction can be calculated as follows:

[0120] ;

[0121] For and normalize them, and the unit vectors for control corner point 2 and control corner point 5 to advance into the airfoil are:

[0122] ;

[0123] Similarly, the internal advancing distances of control corner point 7 and control corner point 10 are also selected as 0.015c. Therefore, the coordinates of control corner point 7 and control corner point 10 can be expressed as:

[0124] ;

[0125] .

[0126] In this embodiment, an example of the grid edge is as Figure 5 shown. The process of generating each first grid edge around the airfoil contour is as follows: There are six grid edges around the airfoil contour, namely grid edge 1 (22), grid edge 2 (23), grid edge 3 (24), grid edge 4 (25), grid edge 5 (26), and grid edge 6 (27), which are represented by edge1, edge2, edge3, edge4, edge5, and edge6 respectively. The starting control corner point number of edge1 is 12, and the ending control corner point number is 13. The starting control corner point number of edge2 is 13, and the ending control corner point number is 14. The starting control corner point number of edge3 is 14, and the ending control corner point number is 15. The starting control corner point number of edge4 is 15, and the ending control corner point number is 16. The starting control corner point number of edge5 is 16, and the ending control corner point number is 17. The starting control corner point number of edge6 is 17, and the ending control corner point number is 12. Among them, grid edges 1 to 5 are distributed on the airfoil and are curved grid edges; grid edge 6 (27) is composed of a straight line between two points and is a straight grid edge; the grid points on grid edge 1 (22), grid edge 3 (24), grid edge 5 (26), and grid edge 6 (27) are evenly distributed; the grid points on grid edge 2 (23) and grid edge 4 (25) are unevenly distributed.

[0127] For the curved grid edges 1, 3, and 5 with evenly distributed grid points, first, from the starting point X S the curvilinear distance from the trailing edge position of the upper airfoil surface and the ending point X e the curvilinear distance from the trailing edge position of the upper airfoil surface The curve distance of the $i$-th grid point on the grid edge is obtained by linear interpolation , which is expressed as:

[0128] ;

[0129] Among them, represents the number of grid points on this grid edge. According to practice, it is more appropriate to set the number of grid points on grid edge one and grid edge five to 5, and the number of grid points on grid edge three to 4. Then, based on the expression of the airfoil geometric parameterization model, , At the four formulas of, and then from The coordinates of the grid points are calculated. The in the following formula can be replaced by 4 and 5, which is expressed as:

[0130] ;

[0131] For the curve grid edges two and four with non-uniformly distributed grid points, the starting and ending grid sizes are obtained by assigning values according to the continuity condition of the adjacent grid edges. Then, according to the number of grid nodes, the starting grid size, and the ending grid size, the distribution coefficient coe of each grid point is obtained according to the Hyperbolic distribution law, and the curve distance of each grid point is calculated. The number of grid points on grid edges two and four is set to 60. Therefore, it is expressed as:

[0132] ;

[0133] Specifically, it can be expressed as:

[0134] ;

[0135] Thus, the coordinates of each grid point.

[0136] For the straight line uniformly distributed grid edge six, it is more reasonable to set the number of grid points on grid edge six to 4. It is directly obtained by linear interpolation of the coordinates of two points. The coordinates of the $i$-th grid point can be expressed as:

[0137] ;

[0138] Specifically, it can be expressed as:

[0139] ;

[0140] Among them, , is the number of grid points on edge6.

[0141] Step S14: Generate each intersecting edge at the leading edge and the trailing edge according to each of the first grid edges, generate the second grid edges inside the airfoil using each of the second control corner points, and generate the target quadrilateral region based on each of the quadrilateral regions, each of the first grid edges, each of the intersecting edges, and each of the second grid edges.

[0142] In this embodiment, the process of generating each intersecting edge at the trailing edge is as follows: As Figure 5 shown, the three grid edges intersecting the airfoil near the trailing edge are grid edge seven 28, grid edge ten 31, and grid edge eleven 32, denoted by edge7, edge10, and edge11. For example, the number of grid points on grid edge eleven 32 is the same as that on grid edge one 22, set to 4. It is also reasonable to set the number of grid points on grid edge seven 28 and grid edge ten 31 to 4. The starting control corner point number of edge7 is 13, and the ending control corner point number is 18. The starting control corner point number of edge10 is 16, and the ending control corner point number is 21. The starting control corner point number of edge11 is 16, and the ending control corner point number is 13. The three grid edges edge7, edge10, and edge11 are all straight grid edges, and the grid points on the grid edges are evenly distributed. The coordinates of the grid points on each grid edge can be expressed as:

[0143] ;

[0144] ;

[0145] ;

[0146] Specifically, it can be expressed as:

[0147] ;

[0148] ;

[0149] .

[0150] In this embodiment, the process of generating each intersecting edge at the leading edge is as follows: As Figure 5 shown, the two grid edges intersecting the airfoil near the leading edge are grid edge eight 29 and grid edge nine 30, denoted by edge8 and edge9. The number of grid points on grid edge eight 29 and grid edge nine 30 is set to be the same as that on grid edge seven 28 and grid edge ten 31, set to 4. The starting control corner point number of edge8 is 14, and the ending control corner point number is 19. The starting control corner point number of edge9 is 15, and the ending control corner point number is 20. The two grid edges edge8 and edge9 are all straight grid edges, and the grid points on the grid edges are evenly distributed. The coordinates of the grid points on each grid edge can be expressed as:

[0151] ;

[0152] ;

[0153] Specifically, it can be expressed as:

[0154] ;

[0155] .

[0156] In this embodiment, the process of generating the second grid edges inside the airfoil is as follows: As Figure 5 shown, the four grid edges inside the airfoil are grid edge twelve 33, grid edge thirteen 34, grid edge fourteen 35, and grid edge fifteen 36, which are represented by edge12, edge13, edge14, and edge15. The number of grid points of grid edge twelve 33 and grid edge fourteen 35 is the same as that of grid edge two 23 and grid edge four 25, which is set to 60. The number of grid points of grid edge thirteen 34 and grid edge fifteen 36 is the same as that of grid edge three 24 and grid edge six 27, which is set to 4. The starting control corner point number of edge12 is 18, and the ending control corner point number is 19. The starting control corner point number of edge13 is 19, and the ending control corner point number is 20. The starting control corner point number of edge14 is 20, and the ending control corner point number is 21. The starting control corner point number of edge15 is 21, and the ending control corner point number is 18. Grid edge twelve 33, grid edge thirteen 34, and grid edge fourteen 35 are curved grid edges, and grid edge fifteen 36 is a straight grid edge; the grid points on grid edge thirteen 34 and grid edge fifteen 36 are evenly distributed, and the grid points on grid edge twelve 33 and grid edge fourteen 35 are unevenly distributed.

[0157] For grid edge twelve, grid edge thirteen, and grid edge fourteen, they can be copied from the existing grid edges. Among them, grid edge thirteen copies grid edge three, adopts a uniform grid point distribution, and the replication ratio coefficient is selected as 0.3. Grid edge twelve copies grid edge two, and the grid size distributions at both ends are taken from the adjacent grid edge thirteen and grid edge fifteen, and the replication ratio coefficient is selected as 0.5. Grid edge fourteen copies grid edge four, and the grid size distributions at both ends are taken from the adjacent grid edge thirteen and grid edge fifteen, and the replication ratio coefficient is selected as 0.5. For grid edge fifteen, linear interpolation is directly adopted, which is expressed as:

[0158] ;

[0159] Specifically, it can be expressed as:

[0160] .

[0161] In this embodiment, the process of assembling and generating six target quadrilateral regions of the airfoil is as follows: The entire airfoil is divided into six quadrilateral regions composed of 15 grid edges, namely quadrilateral region 6, quadrilateral region 7, quadrilateral region 8, quadrilateral region 9, quadrilateral region 10, and quadrilateral region 11, which are represented by surf1, surf2, surf3, surf4, surf5, and surf6. Among them, surf1 is enclosed by grid edge eleven, grid edge five, grid edge six, and grid edge one; surf2 is enclosed by grid edge seven, grid edge two, grid edge eight, and grid edge twelve; surf3 is enclosed by grid edge eight, grid edge three, grid edge nine, and grid edge thirteen; surf4 is enclosed by grid edge nine, grid edge four, grid edge ten, and grid edge fourteen; surf5 is enclosed by grid edge ten, grid edge eleven, grid edge seven, and grid edge fifteen; surf6 is enclosed by grid edge twelve, grid edge thirteen, grid edge fourteen, and grid edge fifteen. Each quadrilateral region is defined according to the right-hand system and assembled with two grid edges in the i direction first and then two grid edges in the j direction. If the grid edge direction is opposite to the i and j directions, it is represented by a negative sign. The six target quadrilateral regions can be assembled as follows:

[0162] 。

[0163] Step S15: Generate a quadrilateral mesh using the target quadrilateral region, construct a computational domain mesh based on the quadrilateral mesh, and perform operations of deleting duplicate grid points, updating the grid point list, and updating the grid cell list on the computational domain mesh to obtain a target grid point list and a target grid cell list.

[0164] In this embodiment, obtain the target quadrilateral region assembly information during the process of generating the target quadrilateral region; use the two-dimensional transfinite interpolation method and generate a quadrilateral mesh based on the target quadrilateral region assembly information, and construct a computational domain mesh including a grid point list and a grid cell list in an unstructured manner defined by a node list and a cell list based on the quadrilateral mesh; delete the duplicate grid points in the grid point list of the computational domain mesh, and perform an update operation on the grid point list to obtain a target grid point list; perform an update operation on the grid cell list according to the mapping relationship between the original grid point number and the updated grid point number to obtain a target grid cell list.

[0165] Specifically, according to the target quadrilateral region assembly information during the process of generating the target quadrilateral region, use the two-dimensional transfinite interpolation method to generate the quadrilateral element mesh of each quadrilateral region.

[0166] In order to generate a structural finite element file and conduct deformation and stress analysis subsequently, the quadrilateral meshes of the six quadrilateral regions are assembled into a computational domain mesh, which is described and output in an unstructured manner defined by a grid point list and a grid cell list.

[0167] Convert the quadrilateral elements generated by structuring each quadrilateral region into an unstructured definition. The number of grid points in the i - direction of the quadrilateral is ni, and the number of grid points in the j - direction is nj. After conversion to the unstructured definition, the number of grid nodes nv is ni * nj, and the number of grid elements nc is (ni - 1) * (nj - 1). The number of the grid point numbered (i, j) in the new grid point list is (j - 1) * ni + i, the number of the grid element numbered (i, j) in the new grid element list is (j - 1) * (ni - 1) + i, and the numbers of the four grid points that make up the unit in the new grid point list are (j - 1) * ni + i, (j - 1) * ni + i + 1, j * ni + i + 1, and j * ni + i respectively.

[0168] After conversion, each quadrilateral region has its own grid point list and grid element list. Then, merge and assemble the grid point lists and grid element lists of the six quadrilateral regions, and update the grid point numbers and element numbers. Add a grid point list (with a total of nv2 nodes) and a grid element list (with a total of nc2 elements) to the existing grid point list (with a total of nv1 nodes) and grid element list (with a total of nc1 elements). Then, the number of each node in the added grid point list is updated from the original i to i + nv1, the number of each element in the added grid element list is updated from the original j to j + nc2, and the numbers of the four grid points in each element are also increased by nv1 respectively. The number of nodes in the new grid point list is nv1 + nv2, and the number of elements is nc1 + nc2. Continuing the above steps, all the grid point lists and grid element lists can be assembled into a unified grid point list and grid element list. The assembled partitioned quadrilateral grid is as Figure 6 shown, and the unified computational domain quadrilateral grid is as Figure 7 shown.

[0169] Since the quadrilateral regions have common grid edges, there are duplicate grid nodes in the directly assembled grid point list, which will cause an error when performing structural finite element analysis. The duplicate grid points need to be deleted. Traverse and search the assembled grid point list, mark the duplicate grid points, and record the numbers of the duplicate grid points. Delete the marked duplicate grid nodes, update the grid point list, record the mapping relationship between the original grid node numbers and the new node numbers, and update the grid point numbers of each grid element in the grid element list according to the mapping relationship.

[0170] Step S16: Generate a grid for the finite element analysis of the quadrilateral structure of the aircraft airfoil according to the target grid point list and the target grid element list.

[0171] In this embodiment, according to the target grid point list and the target grid cell list, combined with the loads and constraint conditions of the structural finite element analysis, the node positions for applying loads and constraints are added to generate a grid file for structural finite element analysis, which is used to obtain the deformation and stress of the airfoil structure under the action of loads.

[0172] In this embodiment, the number and coordinate data of discrete grid points used to describe the geometric shape of the aircraft airfoil are obtained, and the curve distance between the discrete grid points and the trailing edge point of the upper surface of the airfoil is calculated based on the number and the coordinate data; an airfoil geometric parameterization model is established using the curve distance, the airfoil grid is initially segmented to obtain each quadrilateral region, and based on the airfoil geometric parameterization model, the coordinate data, and the curve distance, each first control corner point at the leading edge and the trailing edge corresponding to the upper surface and the lower surface of the airfoil is calculated; each second control corner point inside the airfoil is generated based on each of the first control corner points, and each first grid edge around the airfoil contour is generated using each of the first control corner points and each of the second control corner points; each intersection edge at the leading edge and the trailing edge is generated according to each of the first grid edges, the second grid edge inside the airfoil is generated using each of the second control corner points, and a target quadrilateral region is generated based on each of the quadrilateral regions, each of the first grid edges, each of the intersection edges, and each of the second grid edges; a quadrilateral grid is generated using the target quadrilateral region, and a computational domain grid is constructed based on the quadrilateral grid. Repeated grid point deletion operations, grid point list update operations, and grid cell list update operations are performed on the computational domain grid to obtain a target grid point list and a target grid cell list; a grid for finite element analysis of the quadrilateral structure of the aircraft airfoil is generated according to the target grid point list and the target grid cell list. In this application, the curve distance between the discrete grid points and the trailing edge point of the upper surface of the airfoil is calculated based on the number and coordinate data of the discrete grid points used to describe the geometric shape of the aircraft airfoil, which can accurately describe the geometric shape of the airfoil, establish an airfoil geometric parameterization model, initially segment the airfoil grid to obtain each quadrilateral region, calculate each first control corner point at the leading edge and the trailing edge corresponding to the upper surface and the lower surface of the airfoil, generate each second control corner point inside the airfoil, generate each first grid edge around the airfoil contour using each of the first control corner points and each of the second control corner points, generate each intersection edge at the leading edge and the trailing edge according to each of the first grid edges, generate the second grid edge inside the airfoil using each of the second control corner points, generate a target quadrilateral region, generate a quadrilateral grid using the target quadrilateral region, realize the generation of the quadrilateral grid for each target quadrilateral region, and then assemble it into an overall quadrilateral grid, construct a computational domain grid, perform repeated grid point deletion operations, grid point list update operations, and grid cell list update operations on the computational domain grid to obtain a target grid point list and a target grid cell list, and generate a grid for finite element analysis of the quadrilateral structure of the aircraft airfoil, ensuring the full quadrilateralization of the grid cells and the consistency of the grid cells between different airfoil profiles, and realizing the generation of the grid for finite element analysis of the quadrilateral structure of the aircraft airfoil.

[0173] See Figure 8 As shown, an embodiment of the present invention discloses a grid generation device for finite element analysis of the quadrilateral structure of an aircraft airfoil, which may specifically include:

[0174] A curve distance calculation module 41, configured to obtain the number and coordinate data of discrete grid points for describing the geometric shape of an aircraft airfoil, and calculate the curve distance between the discrete grid points and the trailing edge point of the upper surface of the airfoil based on the number and the coordinate data;

[0175] A first control corner point calculation module 42, configured to establish an airfoil geometric parameterization model by using the curve distance, perform an initial segmentation on the airfoil grid to obtain each quadrilateral region, and calculate each first control corner point at the leading edge and the trailing edge corresponding to the upper surface and the lower surface respectively based on the airfoil geometric parameterization model, the coordinate data, and the curve distance;

[0176] A first grid edge generation module 43, configured to generate each second control corner point inside the airfoil based on each of the first control corner points, and generate each first grid edge around the airfoil contour by using each of the first control corner points and each of the second control corner points;

[0177] A target quadrilateral region generation module 44, configured to generate each intersecting edge at the leading edge and the trailing edge according to each of the first grid edges, generate second grid edges inside the airfoil by using each of the second control corner points, and generate a target quadrilateral region based on each of the quadrilateral regions, each of the first grid edges, each of the intersecting edges, and each of the second grid edges;

[0178] An update module 45, configured to generate a quadrilateral grid by using the target quadrilateral region, construct a computational domain grid based on the quadrilateral grid, and perform operations of repeated grid point deletion, grid point list update, and grid cell list update on the computational domain grid to obtain a target grid point list and a target grid cell list;

[0179] A grid generation module 46, configured to generate a grid for finite element analysis of the quadrilateral structure of the aircraft airfoil according to the target grid point list and the target grid cell list.

[0180] In this embodiment, the number and coordinate data of discrete grid points for describing the geometric shape of the aircraft airfoil are obtained, and the curve distance between the discrete grid points and the trailing edge point of the upper surface of the airfoil is calculated based on the number and the coordinate data; a geometric parameterization model of the airfoil is established by using the curve distance, the airfoil grid is initially segmented to obtain each quadrilateral region, and each first control corner point at the leading edge and the trailing edge corresponding to the upper surface and the lower surface of the airfoil is calculated based on the geometric parameterization model of the airfoil, the coordinate data, and the curve distance; each second control corner point inside the airfoil is generated based on each of the first control corner points, and each first grid edge around the airfoil contour is generated by using each of the first control corner points and each of the second control corner points; each intersection edge at the leading edge and the trailing edge is generated according to each of the first grid edges, the second grid edge inside the airfoil is generated by using each of the second control corner points, and a target quadrilateral region is generated based on each of the quadrilateral regions, each of the first grid edges, each of the intersection edges, and each of the second grid edges; a quadrilateral grid is generated by using the target quadrilateral region, and a computational domain grid is constructed based on the quadrilateral grid. The repeated grid point deletion operation, grid point list update operation, and grid cell list update operation are performed on the computational domain grid to obtain a target grid point list and a target grid cell list; a grid for finite element analysis of the quadrilateral structure of the aircraft airfoil is generated according to the target grid point list and the target grid cell list. Based on the number and coordinate data of discrete grid points for describing the geometric shape of the aircraft airfoil, the curve distance between the discrete grid points and the trailing edge point of the upper surface of the airfoil is calculated, which can accurately describe the geometric shape of the airfoil, establish a geometric parameterization model of the airfoil, initially segment the airfoil grid to obtain each quadrilateral region, calculate each first control corner point at the leading edge and the trailing edge corresponding to the upper surface and the lower surface of the airfoil, generate each second control corner point inside the airfoil, generate each first grid edge around the airfoil contour by using each of the first control corner points and each of the second control corner points, generate each intersection edge at the leading edge and the trailing edge according to each of the first grid edges, generate the second grid edge inside the airfoil by using each of the second control corner points, generate a target quadrilateral region, generate a quadrilateral grid by using the target quadrilateral region, realize the generation of the quadrilateral grid for each target quadrilateral region, and then assemble it into an overall quadrilateral grid, construct a computational domain grid, perform the repeated grid point deletion operation, grid point list update operation, and grid cell list update operation on the computational domain grid to obtain a target grid point list and a target grid cell list, and generate a grid for finite element analysis of the quadrilateral structure of the aircraft airfoil, ensuring the all-quadrilateralization of grid cells and the consistency of grid cells between different airfoil profiles, and realizing the generation of the grid for finite element analysis of the quadrilateral structure of the aircraft airfoil.

[0181] In some specific embodiments, the curve distance calculation module 41 may specifically include:

[0182] A quantity and coordinate data acquisition module, configured to acquire the quantity and coordinate data of discrete grid points from a preset data file or formula describing the airfoil geometry;

[0183] A trailing edge point determination module, configured to determine the trailing edge point of the upper surface of the airfoil, and calculate the curvilinear distance between the discrete grid points and the trailing edge point of the upper surface of the airfoil based on the quantity and the coordinate data and by using a curvilinear distance calculation formula; the curvilinear distance calculation formula is:

[0184] ;

[0185] ;

[0186] Wherein, is the curvilinear distance of the i-th discrete grid point, is the curvilinear distance of the (i - 1)-th discrete grid point, n is the quantity of discrete grid points, is the straight-line distance between the (i - 1)-th discrete grid point and the i-th discrete grid point, is the coordinate data of the i-th discrete grid point, is the coordinate data of the (i - 1)-th discrete grid point.

[0187] In some specific embodiments, the first control corner point calculation module 42 may specifically include:

[0188] An airfoil geometric parameterization model establishment module, configured to establish an airfoil geometric parameterization model by using the curvilinear distance and adopting a one-dimensional radial basis interpolation method; the expression of the airfoil geometric parameterization model is:

[0189] ;

[0190] Wherein, f is an interpolation function, n is the quantity of discrete grid points, is the curvilinear distance, is an interpolation coefficient, is a basis function, and d is an interpolation variable.

[0191] In some specific embodiments, the first control corner point calculation module 42 may specifically include:

[0192] A first control corner point determination module at the trailing edge, configured to determine the first control corner point at the trailing edge of the upper surface of the airfoil and the first control corner point at the trailing edge of the lower surface of the airfoil based on the coordinate data;

[0193] The first control corner point determination module within the trailing edge control corner point range is configured to perform planar coordinate calculations on the coordinate data, the preset trailing edge control corner point range, and the curve distance by using the airfoil geometric parameterization model, so as to obtain the first control corner point on the upper airfoil within the preset trailing edge control corner point range and the first control corner point on the lower airfoil within the preset trailing edge control corner point range;

[0194] The first control corner point determination module within the leading edge control corner point range is configured to perform iterative calculations on the curve distance based on the bisection method to obtain the leading edge control corner point range, and perform planar coordinate calculations on the coordinate data, the leading edge control corner point range, and the curve distance by using the airfoil geometric parameterization model, so as to obtain the first control corner point on the upper airfoil within the leading edge control corner point range and the first control corner point on the lower airfoil within the leading edge control corner point range.

[0195] In some specific embodiments, the first mesh edge generation module 43 may specifically include:

[0196] The second control corner point generation module is configured to advance each of the first control corner points along the inner normal direction of the airfoil, the airfoil tangent direction, and the angular bisector direction of the connection line between the control corner points, so as to generate each second control corner point inside the airfoil.

[0197] In some specific embodiments, the target quadrilateral region generation module 44 may specifically include:

[0198] The assembly information acquisition module is configured to acquire the target quadrilateral region assembly information during the process of generating the target quadrilateral region;

[0199] The quadrilateral mesh generation module is configured to generate a quadrilateral mesh by using a two-dimensional transfinite interpolation method and based on the target quadrilateral region assembly information.

[0200] In some specific embodiments, the update module 45 may specifically include:

[0201] The computational domain mesh construction module is configured to construct a computational domain mesh including a mesh point list and a mesh cell list in an unstructured manner defined by a node list and a cell list based on the quadrilateral mesh;

[0202] The mesh point list update module is configured to delete duplicate mesh points in the mesh point list of the computational domain mesh and perform an update operation on the mesh point list to obtain a target mesh point list;

[0203] The mesh cell list update module is configured to perform an update operation on the mesh cell list according to the mapping relationship between the original mesh point numbers and the updated mesh point numbers to obtain a target mesh cell list.

[0204] Figure 9 This is a schematic structural diagram of an electronic device provided by an embodiment of the present application. The electronic device 50 may specifically include: at least one processor 51, at least one memory 52, a power supply 53, a communication interface 54, an input / output interface 55, and a communication bus 56. Among them, the memory 52 is used to store a computer program, and the computer program is loaded and executed by the processor 51 to implement the relevant steps in the grid generation method for finite element analysis of the airfoil quadrilateral structure of an aircraft executed by the electronic device disclosed in any of the foregoing embodiments.

[0205] In this embodiment, the power supply 53 is used to provide working voltage for each hardware device on the electronic device 50; the communication interface 54 can create a data transmission channel between the electronic device 50 and external devices, and the communication protocol it follows is any communication protocol applicable to the technical solution of the present application, and no specific limitation is imposed on it here; the input / output interface 55 is used to obtain external input data or output data to the outside, and its specific interface type can be selected according to specific application needs, and no specific limitation is made here.

[0206] In addition, as a carrier for resource storage, the memory 52 can be a read-only memory, a random access memory, a magnetic disk, or an optical disc, etc. The resources stored thereon include an operating system 521, a computer program 522, and data 523, etc., and the storage method can be short-term storage or permanent storage.

[0207] Among them, the operating system 521 is used to manage and control each hardware device on the electronic device 50 and the computer program 522 to implement the operation and processing of the data 523 in the memory 52 by the processor 51, and it can be Windows, Unix, Linux, etc. In addition to the computer program that can be used to complete the grid generation method for finite element analysis of the airfoil quadrilateral structure of an aircraft executed by the electronic device 50 disclosed in any of the foregoing embodiments, the computer program 522 can further include computer programs that can be used to complete other specific tasks. In addition to the data that can include the data transmitted from external devices received by the grid generation device for finite element analysis of the airfoil quadrilateral structure of an aircraft, the data 523 can also include the data collected by its own input / output interface 55, etc.

[0208] The steps of the method or algorithm described in combination with the embodiments disclosed in this article can be directly implemented by hardware, a software module executed by a processor, or a combination of the two. The software module can be placed in a random access memory (RAM), memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, register, hard disk, removable disk, CD-ROM, or any other form of storage medium well-known in the technical field.

[0209] Further, an embodiment of the present application also discloses a computer-readable storage medium, in which a computer program is stored. When the computer program is loaded and executed by a processor, the steps of the mesh generation method for the finite element analysis of the quadrilateral structure of the aircraft airfoil disclosed in any of the foregoing embodiments are implemented.

[0210] Finally, it should also be noted that in this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the existence of additional identical elements in the process, method, article or device comprising the element.

[0211] The above has introduced in detail a mesh generation method, device, equipment and storage medium for the finite element analysis of the quadrilateral structure of an aircraft airfoil provided by the present invention. Specific examples are used in this text to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A mesh generation method for finite element analysis of a quadrilateral structure of an aircraft airfoil, characterized in that, Including: Obtain the number and coordinate data of discrete grid points for describing the airfoil geometry of the aircraft, and calculate the curve distance between the discrete grid points and the trailing edge point of the upper surface of the airfoil based on the number and the coordinate data; Establish an airfoil geometric parameterization model using the curve distance, perform an initial segmentation on the airfoil grid to obtain each quadrilateral region, and calculate each first control corner point at the leading edge and trailing edge corresponding to the upper surface and the lower surface respectively based on the airfoil geometric parameterization model, the coordinate data, and the curve distance; Generate each second control corner point inside the airfoil based on each of the first control corner points, and generate each first grid edge around the airfoil contour using each of the first control corner points and each of the second control corner points; Generate each intersecting edge at the leading edge and trailing edge according to each of the first grid edges, generate the second grid edge inside the airfoil using each of the second control corner points, and generate the target quadrilateral region based on each of the quadrilateral regions, each of the first grid edges, each of the intersecting edges, and each of the second grid edges; Generate a quadrilateral grid using the target quadrilateral region, and construct a computational domain grid based on the quadrilateral grid, and perform operations of repeated grid point deletion, grid point list update, and grid cell list update on the computational domain grid to obtain a target grid point list and a target grid cell list; Generate a grid for finite element analysis of the quadrilateral structure of the aircraft airfoil according to the target grid point list and the target grid cell list.

2. The grid generation method for finite element analysis of the quadrilateral structure of the aircraft airfoil according to claim 1, wherein, The obtaining the number and coordinate data of discrete grid points for describing the airfoil geometry of the aircraft, and calculating the curve distance between the discrete grid points and the trailing edge point of the upper surface of the airfoil based on the number and the coordinate data includes: Obtain the number and coordinate data of discrete grid points from a preset data file or formula for describing the airfoil geometry; Determine the trailing edge point of the upper surface of the airfoil, and calculate the curve distance between the discrete grid points and the trailing edge point of the upper surface of the airfoil based on the number and the coordinate data using a curve distance calculation formula; the curve distance calculation formula is: ； ； Among them, is the curve distance of the i-th discrete grid point, is the curve distance of the (i - 1)-th discrete grid point, and n is the number of discrete grid points, is the straight-line distance between the (i - 1)-th discrete grid point and the i-th discrete grid point, is the coordinate data of the i-th discrete grid point, is the coordinate data of the (i - 1)-th discrete grid point.

3. The grid generation method for the finite element analysis of the quadrilateral structure of the aircraft airfoil according to claim 1, wherein The establishing an airfoil geometric parameterization model using the curve distance includes: Establish an airfoil geometric parameterization model using the curve distance and adopting a one-dimensional radial basis interpolation method; the expression of the airfoil geometric parameterization model is: ； where f is the interpolation function, n is the number of discrete grid points, is the curve distance, is the interpolation coefficient, is the basis function, and d is the interpolation variable.

4. The mesh generation method for finite element analysis of the airfoil quadrilateral structure of an aircraft according to claim 1, characterized in that, The calculating each first control corner point at the leading edge and trailing edge corresponding to the upper surface and the lower surface respectively based on the airfoil geometric parameterization model, the coordinate data, and the curve distance includes: Determine the first control corner point at the trailing edge of the upper surface of the airfoil and the first control corner point at the trailing edge of the lower surface of the airfoil based on the coordinate data; Perform plane coordinate calculation on the coordinate data, a preset trailing edge control corner point range, and the curve distance using the airfoil geometric parameterization model to obtain the first control corner points within the preset trailing edge control corner point range of the upper surface and the first control corner points within the preset trailing edge control corner point range of the lower surface; Based on the bisection method, the curve distance is iteratively calculated to obtain the leading-edge control corner point range. Using the airfoil geometric parameterization model, plane coordinate calculations are performed on the coordinate data, the leading-edge control corner point range, and the curve distance to obtain the first control corner points within the leading-edge control corner point range of the upper airfoil surface and the first control corner points within the leading-edge control corner point range of the lower airfoil surface.

5. The mesh generation method for the finite element analysis of the quadrilateral structure of the aircraft airfoil according to claim 1, wherein Generating each second control corner point inside the airfoil based on each of the first control corner points includes: Advancing each of the first control corner points along the inner normal direction of the airfoil, the airfoil tangent direction, and the angular bisector direction of the line connecting the control corner points to generate each second control corner point inside the airfoil.

6. The mesh generation method for the finite element analysis of the airfoil quadrilateral structure of an aircraft according to claim 1, characterized in that, Generating a quadrilateral mesh using the target quadrilateral region includes: Obtaining the target quadrilateral region assembly information during the process of generating the target quadrilateral region; Generating a quadrilateral mesh using the two-dimensional transfinite interpolation method and based on the target quadrilateral region assembly information.

7. The mesh generation method for finite element analysis of the quadrilateral structure of an aircraft airfoil according to any one of claims 1 to 6, characterized in that, Constructing a computational domain mesh based on the quadrilateral mesh and performing operations of deleting duplicate mesh points, updating the mesh point list, and updating the mesh element list on the computational domain mesh to obtain a target mesh point list and a target mesh element list includes: Constructing a computational domain mesh including a mesh point list and a mesh element list in an unstructured manner defined by a node list and an element list based on the quadrilateral mesh; Deleting the duplicate mesh points in the mesh point list of the computational domain mesh and performing an update operation on the mesh point list to obtain a target mesh point list; Performing an update operation on the mesh element list according to the mapping relationship between the original mesh point numbers and the updated mesh point numbers to obtain a target mesh element list.

8. A grid generation device for finite element analysis of an airfoil quadrilateral structure of an aircraft, characterized in that, Includes: A curve distance calculation module for obtaining the number and coordinate data of discrete mesh points describing the geometric shape of the aircraft airfoil and calculating the curve distance between the discrete mesh points and the trailing-edge point of the upper airfoil surface of the airfoil; A first control corner point calculation module for establishing an airfoil geometric parameterization model using the curve distance, initially dividing the airfoil mesh to obtain each quadrilateral region, and calculating each first control corner point at the leading edge and trailing edge corresponding to the upper airfoil surface and the lower airfoil surface respectively based on the airfoil geometric parameterization model, the coordinate data, and the curve distance; A first mesh edge generation module for generating each second control corner point inside the airfoil based on each of the first control corner points and generating each first mesh edge around the airfoil contour using each of the first control corner points and each of the second control corner points; A target quadrilateral region generation module for generating each intersecting edge at the leading edge and trailing edge according to each of the first mesh edges, generating second mesh edges inside the airfoil using each of the second control corner points, and generating a target quadrilateral region based on each of the quadrilateral regions, each of the first mesh edges, each of the intersecting edges, and each of the second mesh edges; An update module, configured to generate a quadrilateral mesh by using the target quadrilateral region, construct a computational domain mesh based on the quadrilateral mesh, and perform repeated grid point deletion operations, grid point list update operations, and grid cell list update operations on the computational domain mesh to obtain a target grid point list and a target grid cell list; A mesh generation module, configured to generate a mesh for finite element analysis of an aircraft airfoil quadrilateral structure according to the target grid point list and the target grid cell list.

9. An electronic device, characterized in that, Comprising: A memory, configured to store a computer program; A processor, configured to execute the computer program to implement the mesh generation method for finite element analysis of an aircraft airfoil quadrilateral structure according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, For storing a computer program; wherein, when the computer program is executed by the processor, the mesh generation method for finite element analysis of an aircraft airfoil quadrilateral structure according to any one of claims 1 to 7 is implemented.

Images