A mesh deformation method and device based on adaptive mesh boundary deformation

Abstract

The present application provides a mesh deformation method and device based on adaptive mesh boundary deformation, which belongs to the field of aerospace. The method includes: obtaining an initial control point set; deforming the mesh to be deformed based on the initial control point set and the RBF method; obtaining the maximum boundary deformation point based on the deformed mesh; updating the initial control point set based on the maximum boundary deformation point, returning to the step of deforming the mesh to be deformed based on the initial control point set and the RBF method until the total deformation of the mesh to be deformed meets a preset threshold; generating a control point set for the mesh to be deformed based on the updated initial control point set; deforming the mesh to be deformed based on the control point set. The mesh deformation method and device based on adaptive mesh boundary deformation provided by the present application can ensure the accuracy of calculation while using less calculation time and memory cost.

Description

Technical Field

[0001] The present application relates to the field of aerospace technology, and in particular to a mesh deformation method and device based on adaptive mesh boundary deformation. Background Art

[0002] In the field of aerospace, the design and performance optimization of aircraft is a complex and critical process. Designers build various precise simulation models to study the performance of aircraft under different flight conditions. Among them, the design of aircraft engines is particularly important, and the three-dimensional model of the blades in the engine is one of the key factors affecting engine performance. The shape, structure and working state of the blades have a profound impact on the engine's efficiency, thrust and other performance indicators.

[0003] In order to better optimize the performance of the engine, it is often necessary to conduct deformation research on the three-dimensional model of the blade. For example, the design of the blade in the axial compressor, its full three-dimensional aerodynamic optimization has the characteristics of high optimization variable dimension and expensive evaluation. In this process, the grid generation and flow field iterative calculation part are the most time-consuming. In order to meet the needs of optimization calculation, it is necessary to develop a flow field boundary grid control method to improve the accuracy of direct grid deformation flow field calculation.

[0004] At present, mesh boundary control can be achieved in the following three ways: first, directly fix the mesh boundary, introduce all single-row flow field meshes into the area to be deformed, and directly use the original mesh boundary to replace the deformed boundary after deformation to ensure that the boundary remains unchanged. This method is simple to implement and does not require the introduction of additional control points, but it is easy to cause a large number of negative meshes at the mesh boundary, affecting the solution accuracy; second, selectively introduce mesh blocks. Since the flow field boundary meshes are all in the outer layer, only the blade mesh block can be introduced into the area to be deformed. There is no need to introduce additional control points, but the blade mesh block is wrapped as a whole by the outer layer block. The movement of the inner mesh boundary will cause the inner and outer meshes to be unable to fit together, resulting in a large number of negative meshes; third, introduce mesh boundary control points. By distributing control points on the mesh boundary, the boundary mesh displacement is reduced, and the overall flow field mesh is "framed" with a denser frame. Therefore, in order to ensure the accuracy of the calculation, the third method is often used for boundary control. However, after the boundary control operation, the number of control points increases sharply, resulting in a significant increase in the calculation time and memory resources required for the boundary control method. Therefore, how to reduce the calculation time and memory cost and ensure the accuracy of the calculation is an urgent problem to be solved. Summary of the invention

[0005] In view of this, the present application provides a mesh deformation method and device based on adaptive mesh boundary deformation, which can ensure the accuracy of calculation while utilizing less calculation time and memory cost.

[0006] Specifically, the present application is implemented through the following technical solutions:

[0007] In a first aspect, the present application provides a mesh deformation method based on adaptive mesh boundary deformation, the method comprising:

[0008] Get the initial control point set;

[0009] Deforming the mesh to be deformed based on the initial control point set and the RBF method;

[0010] Obtain the maximum deformation point of the boundary based on the deformed mesh;

[0011] Wherein, the maximum deformation point is determined according to the displacement of the boundary grid points of the deformed grid;

[0012] The initial control point set is updated based on the maximum deformation point of the boundary, and the step of deforming the to-be-deformed mesh based on the initial control point set and the RBF method is returned until the total deformation amount of the to-be-deformed mesh meets a preset threshold;

[0013] Generating a control point set of the to-be-deformed mesh according to the updated initial control point set;

[0014] The mesh to be deformed is deformed based on the set of control points.

[0015] A second aspect of the present application provides a mesh deformation device based on adaptive mesh boundary deformation, the device comprising an acquisition module, a deformation module, an update module and a generation module; wherein;

[0016] The acquisition module is used to acquire an initial control point set;

[0017] The deformation module is used to deform the grid to be deformed based on the initial control point set and the RBF method;

[0018] The acquisition module is further used to acquire the maximum deformation point of the boundary based on the deformed grid;

[0019] Wherein, the maximum deformation point is determined according to the displacement of the boundary grid points of the deformed grid;

[0020] The updating module is used to update the initial control point set based on the maximum deformation point of the boundary, and return to the step of deforming the to-be-deformed mesh based on the initial control point set and the RBF method until the total deformation amount of the to-be-deformed mesh meets a preset threshold;

[0021] The generating module is used to generate the control point set of the to-be-deformed mesh according to the updated initial control point set;

[0022] The deformation module is further used to deform the mesh to be deformed based on the control point set.

[0023] The mesh deformation method and device based on adaptive mesh boundary deformation provided by the present application obtain an initial control point set, use the RBF method to perform deformation, and then obtain the maximum deformation point of the boundary according to the deformed mesh to update the initial control point set, thereby avoiding the uncontrolled increase in the number of control points, thereby reducing the waste of computing time and memory resources caused by too many control points, and effectively controlling the number of control points; and on the premise of meeting the preset threshold of the total deformation amount of the mesh to be deformed, continuously updating the control point set, making the mesh deformation process more efficient, reducing unnecessary calculations, and improving calculation efficiency; in addition, based on an adaptive method, the initial control point set is gradually updated to the control point set that meets the conditions, so that the mesh deformation process can better adapt to the deformation requirements of the blade three-dimensional model, thereby improving the accuracy and stability of the deformation. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A flowchart of a first embodiment of a mesh deformation method based on adaptive mesh boundary deformation provided by the present application;

[0025] Figure 2 A comparison diagram of a mesh deformation method based on adaptive mesh boundary deformation according to an exemplary embodiment of the present application;

[0026] Figure 3 A comparison diagram of adaptive RBF calculation and verification calculation results shown in an exemplary embodiment of the present application;

[0027] Figure 4 A comparison diagram of mesh vertex control deformation calculation and verification calculation results shown in an exemplary embodiment of the present application;

[0028] Figure 5 This is a structural schematic diagram of Embodiment 1 of a grid deformation device based on adaptive grid boundary deformation provided in the present application. DETAILED DESCRIPTION

[0029] Here, exemplary embodiments are described in detail, and examples thereof are shown in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application.

[0030] The terms used in this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The singular forms of "a", "said" and "the" used in this application are also intended to include plural forms, unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used in this article refers to and includes any or all possible combinations of one or more associated listed items.

[0031] It should be understood that although the terms first, second, third, etc. may be used in the present application to describe various information, these information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of the present application, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining".

[0032] Specific embodiments are given below to introduce the technical solution of the present application in detail.

[0033] Figure 1 This is a flow chart of the first embodiment of the mesh deformation method based on adaptive mesh boundary deformation provided by this application. Figure 1 , the method provided in this embodiment may include:

[0034] S101. Obtain an initial control point set.

[0035] Specifically, obtaining the initial control point set includes:

[0036] (1) Read the CGNS file, determine the flow field grid area to be deformed and generate the original grid point set.

[0037] It should be noted that CGNS (CFD General Notation System) is a standard file format for storing and exchanging CFD (Computational Fluid Dynamics) data, developed by NASA, Boeing, Lockheed Martin, and the US Air Force. It can be used to store information such as geometric meshes, physical models, and numerical results in CFD calculations, and supports a variety of CFD solvers and post-processing software (CFview, Tecplot, etc.). CGNS files use a structured binary storage method to improve data reading and writing efficiency, and a hierarchical storage method facilitates data stratification and management.

[0038] Specifically, a CGNS file consists of two main parts: a file header and a data area. The file header contains metadata and structural information of the file, such as the CGNS version number, file description, mesh type, physical model, etc. The file header consists of structured text and can be read and written through a text editor or the corresponding functions in the CGNS library. The data area contains actual data, such as mesh coordinates, mesh topology, boundary conditions, flow field data, etc. The data area is a hierarchical structure consisting of multiple nodes and links, and each node can contain one or more data items.

[0039] By reading the CGNS file, we can get the information such as the position of each grid point, the grid block array structure, the CGNS file tree and the position of the grid node, so as to determine the area of ​​the flow field grid to be deformed, extract all the original grid points in the area, and generate the original grid point set. In specific implementation, the CGNS file can be read through the pycgns library function, where pycgns is a Python extension library for reading and writing CGNS files. It is developed based on the CGNS C language library and provides a series of Python interface functions to easily read and modify the data in the CGNS file.

[0040] (2) Setting blade deformation control points and original grid boundary control points based on the original grid point set to obtain an initial control point set.

[0041] It should be noted that specific grid points are selected from the original grid point set, for example, these points can be points in the original grid point set close to or located in the blade area, and these points are used as control points for blade deformation to accurately control the deformation of the blade area. Specifically, the blade deformation control points can be selected to be located at 0.3 chord lengths on the suction surface of 10% and 60% blade height, and at 0.6 chord lengths on the pressure surface of 30% and 90% blade height, respectively, and the blade deformation control points limit spanwise and chordwise movement.

[0042] The points located at the boundary of the mesh are selected from the original mesh point set and used as boundary control points to control and maintain the shape and structure of the boundary. In addition, the vertices of each mesh block are used as initial control points to ensure that the structure of the entire mesh is well controlled during the deformation process.

[0043] In this way, based on the original grid point set, the blade deformation control points and the original grid boundary control points are set to form an initial control point set, which ensures accurate control of key areas and boundary areas and facilitates subsequent grid deformation.

[0044] S102, deforming the grid to be deformed based on the initial control point set and the RBF method.

[0045] It should be noted that the deformation of the deformed mesh based on the initial control point set and the RBF (Radial Basis Function) method includes:

[0046] (1) Determine a first control point set after deformation based on the deformation requirement and the initial control point set.

[0047] It should be noted that the deformation requirements may include information such as the moving range and movement amount of the deformation control points. According to the deformation requirements and combined with the information of the initial control points, the positions of the deformation control points and boundary control points of the deformed blades can be obtained, and the positions of the deformation control points and boundary control points of the deformed blades and other information can be combined to obtain the first control point set.

[0048] (2) Calculating the distance between each control point in the first control point set and the initial control point set, and determining the deformation parameters of the RBF method according to the distance; the deformation parameters include at least weights, polynomial terms, basis function types, and shape parameters.

[0049] It should be noted that the RBF method is a powerful tool for interpolation and fitting, and is widely used in the fields of mesh deformation, image deformation, data interpolation, and machine learning. The RBF method is based on a set of control points and describes the deformation or interpolation process by constructing an interpolation function. Specifically, for a detailed description of how to deform a deformed mesh based on the RBF method, please refer to the introduction of the related technology, which will not be repeated here.

[0050] It should also be noted that the weights in the deformation parameters are used to propagate the influence of the control points to other points in the entire mesh; the types of basis functions in the deformation parameters usually include Gaussian basis functions, bi-cospline basis functions, etc.; the shape parameters in the deformation parameters are used to control the shape and influence range of the basis functions; the polynomial terms in the deformation parameters are used to ensure affine invariance, so that the mesh deformation is not only affected by the local control points, but also maintains the overall shape.

[0051] (3) Deforming the mesh to be deformed according to the RBF method for determining deformation parameters.

[0052] It should be noted that after the deformation parameters of the RBF method are determined, the deformed mesh can be deformed based on the RBF method. Specifically, the RBF method is an interpolation method that derives the values ​​of other points by using the known values ​​on the control points (i.e., the initial control point set and the deformed control point set). Once the weights are determined, an interpolation function can be constructed to estimate the positions of other points in the mesh; in addition, the RBF method has the characteristics of local control, that is, each control point has a limited influence on the surrounding area. By selecting the appropriate basis function type and shape parameters, the influence range and shape can be adjusted, so that the deformation process has high flexibility and accuracy in the local area.

[0053] S103, obtaining a maximum deformation point of a boundary based on the deformed grid; wherein the maximum deformation point is determined according to the displacement of the boundary grid points of the deformed grid.

[0054] Specifically, obtaining the maximum deformation point of the boundary based on the deformed grid includes: identifying the grid boundary based on the deformed grid; extracting boundary points based on the grid boundary; calculating the position change of each boundary point before and after deformation to obtain the absolute deformation of each boundary point to form an absolute deformation set; traversing the absolute deformation set to obtain the boundary point with the largest absolute deformation value in the absolute deformation set as the maximum deformation point of the grid boundary. Among them, identifying the grid boundary can be done by checking whether the adjacent points of each grid point belong to the same grid and whether there are unconnected neighboring points. After determining the boundary of the grid, boundary points can be extracted. These boundary points are the points where the position change is most obvious in the deformed grid because they are located outside the grid or in contact with other grid areas. For each boundary point, the position change before and after deformation is calculated to obtain the absolute deformation set of all boundary points.

[0055] It should be noted that the position and amount of the maximum deformation point can intuitively reflect the degree of mesh deformation and the concentration of local deformation. The position and amount of the maximum deformation point can help determine the appropriate boundary conditions, which in turn affects the accuracy and reliability of the calculation results. In addition, the maximum deformation point can be used as the starting point for subsequent mesh post-processing, for example, it can be used as an indicator or constraint in the optimization algorithm to help automate the optimization process.

[0056] S104, updating the initial control point set based on the maximum deformation point of the boundary, and returning to the step of deforming the to-be-deformed mesh based on the initial control point set and the RBF method until the total deformation amount of the to-be-deformed mesh meets a preset threshold.

[0057] It should be noted that after updating the initial control point set based on the maximum deformation point of the boundary, the process returns to the step of deforming the deformed grid based on the initial control point set and the RBF method to re-deform the grid and obtain the maximum deformation point of the boundary.

[0058] It should also be noted that until the total deformation of the mesh to be deformed meets the preset threshold, the method specifically includes: obtaining the number of generations of the current iteration and the displacement of the boundary grid points of the deformed mesh; determining whether to stop updating the initial control point set according to the relationship between the number of generations of the current iteration and the preset target number of iterations or the relationship between the displacement of the boundary grid points of the deformed mesh and the displacement of the preset boundary grid points. Wherein, the number of generations of the current iteration is also obtained while deforming the mesh to be deformed to obtain a new mesh based on the initial control point set and the RBF method. Specifically, when the number of generations of the current iteration is greater than the preset target number of iterations or the displacement of the boundary grid points of the deformed mesh is less than the displacement of the preset boundary grid points, the initial control point set is stopped from being updated, and the current control point set is exported for subsequent optimization operations, and a CGNS file is generated when the deformed mesh is exported. For example, in one embodiment, the displacement of the preset boundary grid points is 0.2 cm, the preset threshold of the total deformation of the mesh to be deformed is 0.001 cm, and the preset target number of iterations is 300.

[0059] As an optional embodiment, after updating the initial control point set based on the maximum deformation point of the boundary, the method further includes: determining the difference between the deformed mesh and the total deformation; determining the position point whose deformation difference is greater than a threshold value based on the difference as a newly added deformation point; adding the newly added deformation point to the initial control point set as the updated initial control point set. Specifically, adding the newly added deformation point to the initial control point set includes: determining the control radius of each point in the initial control point set; determining the deformation range of the initial control point set according to the control radius; determining the position relationship between the position of the newly added deformation point to be added and the deformation range; screening the newly added deformation point based on the position relationship and the deformation difference at the newly added deformation point; and adding the screened newly added deformation point to the initial control point set.

[0060] The method provided by the present invention, in order to avoid the situation that the control points surge in the traditional blade mesh deformation process, firstly limits the number of control points by determining the initial control point set, and then in the mesh deformation iteration process, only introduces the maximum deformation point of the boundary each time to increase the number of control points of the initial control point set slightly, so that the deformation target is met more quickly, and only a small number of points are introduced each time, and the number of control points is strictly controlled. In the deformation process of the blade mesh model, different shapes have different deformation requirements for different positions of the blade. At this time, based on the initial control points, in each deformation iteration process, find the point with the largest difference from the deformation target, or the point with a target difference greater than a threshold, and add it in the next round of iteration process, so that the deformation of the blade can be completed quickly on the basis of adding a small number of control points. Further, before deforming the deformed mesh according to the updated initial control point set, the method also includes determining the position of the original control point in the updated initial control point set, and screening the original control point based on the deformation difference at the position of the original control point. The original control point refers to the point that already exists in the initial control point set in the current iteration cycle, and is not newly added, which includes the most original initial control point and the point added and not deleted in the previous iteration cycle. Screening includes removal. If the difference between the current deformation degree and the target deformation degree is less than the threshold, the deformation of the position can be completed by the deformation of other points. At this time, it is no longer necessary to include it in the control points, which further reduces the number of control points and improves the efficiency of deformation.

[0061] Furthermore, the updating of the initial control point set based on the maximum deformation point of the boundary includes: determining a first control point in the initial control point set that is adjacent to the position of the maximum deformation point of the boundary; calculating an overlapping control range of the first control point and the maximum deformation point of the boundary according to a control radius of the first control point and a control radius of the maximum deformation point of the boundary; predicting a deformation degree of the boundary in the overlapping control range; and adjusting the deformation radius of the maximum deformation point and the first control point based on the deformation degree.

[0062] The deformation is determined by the basis function, the control point, and the control radius. In conjunction with the change of the control point, the present invention also provides a method for determining the control radius. After each introduction of a new control point, it can be determined whether to adjust the control radius of the relevant point based on the difference between the predicted deformation degree and the target deformation degree. The control radius of the relevant point is adjusted based on the degree of overlap with the radius covered by the original control point. The adjustment may include reducing the control radius. At this time, when the gap is less than the threshold, in order to avoid the phenomenon of two points controlling the same area, the control point with the deformation amplitude closest to the target deformation degree can be used to control it; the adjustment may also include expanding the control radius. At this time, when the gap is greater than the threshold, one point has no way to complete the deformation requirement of the position as soon as possible. Therefore, the influence of the control point on the overlap range can be expanded. The two control points act on the same area together, which improves the efficiency of deformation.

[0063] S105 , generating a control point set of the to-be-deformed mesh according to the updated initial control point set.

[0064] After generating the control point set of the mesh to be deformed according to the updated initial control point set, the method further includes: determining the actual control points of the mesh to be deformed based on the control point set; solving the deformed coordinates of each mesh in the mesh to be deformed based on the actual control points and the RBF method, and controlling the deformation of the mesh to be deformed. Specifically, the shape adjustment of the mesh to be deformed can be effectively controlled and realized through the above operations to meet the requirements of mesh deformation accuracy and stability in applications.

[0065] S106: deforming the to-be-deformed mesh based on the control point set.

[0066] It should be noted that the specific operations on deforming the deformed mesh based on the control point set can be found in the introduction of related technologies, which will not be described in detail here.

[0067] The mesh deformation method based on adaptive mesh boundary deformation provided in this embodiment obtains an initial control point set, deforms using the RBF method, and then obtains the maximum deformation point of the boundary according to the deformed mesh to update the initial control point set, thereby avoiding the uncontrolled increase in the number of control points, thereby reducing the waste of computing time and memory resources caused by too many control points, and effectively controlling the number of control points; and under the premise of meeting the preset threshold of the total deformation of the mesh to be deformed, the control point set is continuously updated to make the mesh deformation process more efficient, reduce unnecessary calculations, and improve calculation efficiency; in addition, based on an adaptive method, the initial control point set is gradually updated to the control point set that meets the conditions, so that the mesh deformation process can better adapt to the deformation requirements of the blade three-dimensional model, and improve the accuracy and stability of the deformation. Compared with the traditional method, under the condition that the maximum deformation of the boundary mesh remains basically unchanged, the method can greatly reduce the number of total control points, thereby reducing the calculation time, and compared with the dense control method, the maximum time of single-step mesh deformation is reduced, and the mesh generation time and memory resources are greatly reduced.

[0068] The following is an explanation based on the verification test:

[0069] Figure 2 This is a comparison diagram of a mesh deformation method based on adaptive mesh boundary deformation shown in an exemplary embodiment of the present application. Please refer to Figure 2 , it can be seen that when the maximum deformation of the boundary grid remains basically unchanged, the adaptive point arrangement algorithm can greatly reduce the number of total control points and reduce the calculation time.

[0070] Table 1 shows the flow field calculation results of the adaptive point placement algorithm and the comparison with the boundary control. Please refer to Table 1:

[0071] Table 1 Comparison of flow field calculation results of adaptive point placement algorithm and boundary control

[0072] Control Points Dense border control efficiency Verification efficiency Adaptive RBF deformation control efficiency Verification efficiency Boundary control points Boundary control calculation time (s) Adaptive RBF control points Adaptive RBF deformation time (s) Mesh generation time (s) 1 0.8062 0.806 0.8052 0.805 1816 8.2 320 1.3 15.5 2 0.8081 0.8095 0.8076 0.8074 1816 8.1 320 1.2 15.4 3 0.8338 0.8338 0.8335 0.8334 1813 8.6 320 1.3 14.8 4 0.8333 0.8329 0.8332 0.833 1813 8.1 320 1.4 16.1

[0073] In order to further verify the accuracy of the flow field calculation of the adaptive boundary point distribution algorithm, 200 sets of data were randomly calculated, and the full three-dimensional CFD calculation was performed using the adaptive boundary control RBF direct grid flow field deformation method and the geometry export regeneration grid method (verification). The calculated efficiency absolute error is as follows: Figure 3 Please refer to Figure 3 ,It can be seen that within the range of parameter variation, the ,adaptive deformable RBF method is in good agreement with the ,validation calculation results, with a maximum absolute error of 0.167 percentage points and an average ,absolute error of 0.0287 percentage points. Figure 4The results of mesh vertex control deformation calculation and verification calculation are compared, where the gray area is the error band of adaptive RBF calculation. The maximum absolute error of mesh vertex control is 3.53 percentage points. The average absolute error is 0.3518 percentage points. It can be seen that the adaptive RBF deformation method has greatly reduced the calculation error compared with the mesh vertex control method. Compared with the dense control method, the maximum time of single-step mesh deformation is 1.35 seconds, and the mesh generation time and memory resources are greatly reduced.

[0074] Corresponding to the aforementioned embodiment of a mesh deformation method based on an adaptive mesh boundary, the present application also provides an embodiment of a mesh deformation device based on an adaptive mesh boundary.

[0075] Figure 5 This is a structural diagram of the first embodiment of the grid deformation device based on adaptive grid boundary deformation provided by the present application. Figure 5 , the device provided in this embodiment includes an acquisition module 510, a deformation module 520, an update module 530 and a generation module 540; wherein;

[0076] The acquisition module 510 is used to acquire an initial control point set;

[0077] The deformation module 520 is used to deform the mesh to be deformed based on the initial control point set and the RBF method;

[0078] The acquisition module 510 is further used to acquire the maximum deformation point of the boundary based on the deformed grid;

[0079] Wherein, the maximum deformation point is determined according to the displacement of the boundary grid points of the deformed grid;

[0080] The updating module 530 is used to update the initial control point set based on the maximum deformation point of the boundary, and return to the step of deforming the to-be-deformed mesh based on the initial control point set and the RBF method until the total deformation amount of the to-be-deformed mesh meets a preset threshold;

[0081] The generating module 540 is used to generate the control point set of the to-be-deformed mesh according to the updated initial control point set;

[0082] The deformation module 520 is further configured to deform the mesh to be deformed based on the control point set.

[0083] The device of this embodiment can be used to perform Figure 1 The steps, specific implementation principles and implementation processes of the method embodiment shown are similar and will not be repeated here.

[0084] The implementation process of the functions and effects of each unit in the above-mentioned device is specifically described in the implementation process of the corresponding steps in the above-mentioned method, and will not be repeated here.

[0085] For the device embodiment, since it basically corresponds to the method embodiment, the relevant parts can refer to the partial description of the method embodiment. The device embodiment described above is only schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the present application scheme. A person of ordinary skill in the art can understand and implement it without paying any creative work.

[0086] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A mesh deformation method based on adaptive mesh boundary deformation, characterized in that: The method comprises: Get the initial control point set; Deforming the mesh to be deformed based on the initial control point set and the RBF method; Obtain the maximum deformation point of the boundary based on the deformed mesh; Wherein, the maximum deformation point is determined according to the displacement of the boundary grid points of the deformed grid; The initial control point set is updated based on the maximum deformation point of the boundary, and the step of deforming the to-be-deformed mesh based on the initial control point set and the RBF method is returned until the total deformation amount of the to-be-deformed mesh meets a preset threshold; Generating a control point set of the to-be-deformed mesh according to the updated initial control point set; Deforming the to-be-deformed mesh based on the control point set; The deforming the deformed grid based on the initial control point set and the RBF method comprises: Determine a first control point set after deformation based on the deformation requirement and the initial control point set; Calculating the distance between each control point in the first control point set and the initial control point set, and determining the deformation parameter of the RBF method according to the distance; the deformation parameter includes at least weight, polynomial term, basis function type, and shape parameter; Deforming the mesh to be deformed according to the RBF method for determining deformation parameters; The step of obtaining the maximum deformation point of the boundary based on the deformed grid comprises: Identify mesh boundaries based on the deformed mesh; Extracting boundary points based on the grid boundary; Calculating the position change of each boundary point before and after the deformation to obtain the absolute deformation amount of each boundary point to form an absolute deformation amount set; The absolute deformation amount set is traversed to obtain a boundary point with the largest absolute deformation amount value in the absolute deformation amount set as the maximum deformation point of the grid boundary.

2. The method according to claim 1, characterized in that The obtaining of the initial control point set comprises: Read the CGNS file, determine the flow field grid area to be deformed and generate the original grid point set; The blade deformation control points and the original grid boundary control points are set based on the original grid point set to obtain an initial control point set.

3. The method according to claim 1, characterized in that The step of waiting until the total deformation amount of the to-be-deformed mesh meets a preset threshold specifically includes: Get the displacement of the boundary grid points of the algebraic and deformed grid of the current iteration; Whether to stop updating the initial control point set is determined according to the magnitude relationship between the number of generations of the current iteration and a preset target number of iterations or the magnitude relationship between the displacement of the boundary grid points of the deformed grid and the displacement of the preset boundary grid points.

4. The method according to claim 1, characterized in that: After generating the control point set of the to-be-deformed mesh according to the updated initial control point set, the method further comprises: Determine actual control points of the mesh to be deformed based on the control point set; The deformed coordinates of each grid in the grid to be deformed are solved based on the actual control points and the RBF method to control the deformation of the grid to be deformed.

5. The method according to claim 1, characterized in that After the initial control point set is updated based on the maximum deformation point of the boundary, the method further includes: Determine the difference between the deformed mesh and the total deformation; Based on the difference, determine a position point where the deformation difference is greater than a threshold value as a newly added deformation point; The newly added deformation point is added to the initial control point set as the updated initial control point set.

6. The method according to claim 5, characterized in that The adding the newly added deformation point to the initial control point set includes: Determine the control radius of each point in the initial control point set; Determining a deformation range of the initial control point set according to the control radius; Determine the position relationship between the position of the newly added deformation point to be added and the deformation range; Filter the newly added deformation points based on the positional relationship and the deformation gap at the newly added deformation points; The newly added deformation points after screening are added to the initial control point set.

7. The method according to claim 1, characterized in that The updating of the initial control point set based on the maximum deformation point of the boundary comprises: Determine a first control point in the initial control point set that is adjacent to the position of the maximum deformation point of the boundary; Calculate the overlap control range of the first control point and the maximum deformation point of the boundary according to the control radius of the first control point and the control radius of the maximum deformation point of the boundary; Predicting the degree of deformation of the boundary in the overlap control range; The deformation radii of the maximum deformation point and the first control point are adjusted based on the deformation degree.

8. A mesh deformation device based on adaptive mesh boundary deformation, characterized in that: The device comprises an acquisition module, a deformation module, an update module and a generation module; wherein, The acquisition module is used to acquire an initial control point set; The deformation module is used to deform the grid to be deformed based on the initial control point set and the RBF method; The acquisition module is further used to acquire the maximum deformation point of the boundary based on the deformed grid; Wherein, the maximum deformation point is determined according to the displacement of the boundary grid points of the deformed grid; The updating module is used to update the initial control point set based on the maximum deformation point of the boundary, and return to the step of deforming the to-be-deformed mesh based on the initial control point set and the RBF method until the total deformation amount of the to-be-deformed mesh meets a preset threshold; The generating module is used to generate the control point set of the to-be-deformed mesh according to the updated initial control point set; The deformation module is further used to deform the to-be-deformed mesh based on the control point set; The deforming the deformed grid based on the initial control point set and the RBF method comprises: Determine a first control point set after deformation based on the deformation requirement and the initial control point set; Calculating the distance between each control point in the first control point set and the initial control point set, and determining the deformation parameter of the RBF method according to the distance; the deformation parameter includes at least weight, polynomial term, basis function type, and shape parameter; Deforming the mesh to be deformed according to the RBF method for determining deformation parameters; The step of obtaining the maximum deformation point of the boundary based on the deformed grid comprises: Identify mesh boundaries based on the deformed mesh; Extracting boundary points based on the grid boundary; Calculating the position change of each boundary point before and after the deformation to obtain the absolute deformation amount of each boundary point to form an absolute deformation amount set; The absolute deformation amount set is traversed to obtain a boundary point with the largest absolute deformation amount value in the absolute deformation amount set as the maximum deformation point of the grid boundary.

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