Research On Surface Structured Mesh Generation Technology Based On Template

Computational fluid dynamics(CFD)has become an important means of product development in recent years.The importance of mesh generation as the pre-processing stage of CFD is self-evident,and the surface mesh generation in the pre-processing stage is particularly important,which is related to the generation quality of boundary layer mesh and spatial mesh,and the mesh quality directly affects the final solution.At present,unstructured mesh and structured mesh are widely used in engineering applications.compared with unstructured mesh,structured mesh have many advantages,but the low degree of automation has always been the pain point of structured mesh.In the field of engineering,structural mesh mainly depends on manual,time-consuming and laborious,and has high requirements for personnel,so the automatic generation of structural mesh has always been a difficult problem,so it is very necessary to study the technology of automatic generation of structural mesh.At present,the automatic generation method of surface structure mesh based on global conformal parameterization has been proved to be a feasible scheme.In this paper,the core idea of automatic generation of structural mesh is to map the discrete numerical model to the two-dimensional plane through global conformal parameterization,the structural mesh is generated in the two-dimensional plane.finally,the spatial surface structural mesh is obtained by inverse mapping by using the one-to-one corresponding relationship between the triangular mesh before and after parameterization.However,it is difficult to generate two-dimensional structural mesh automatically,and there are generally some problems such as poor mesh transition and low quality for the generation of structural mesh.in order to solve the problem of poor transition and low quality of mesh,a structural mesh generation method based on template is proposed in this paper.The primary problem of structural mesh generation based on template is to get reasonable topology partition results.based on the frame field theory,this paper solves the frame and vector in the boundary and region,and then solves the point where the vector is zero.get the singular point in the region and the inflection point of the boundary,extend a certain number of streamline according to the rule through the singular point and inflection point,and then simplify the streamline,and finally get the simplified topology partition result.In order to solve the problem of closed subregion mesh generation after topology partition,combined with the type of structural mesh template in engineering,a quadrilateral closed sub-region structural mesh filling method suitable for arbitrary point distribution is proposed.The core of this method is to classify the quadrilateral into two kinds of cases according to the parity of the number of edge points of the quadrilateral.The two kinds of templates developed can be used to fill any closed quadrilateral sub-region mesh.Finally,the mesh generation of the actual model shows that this method is feasible and can be used as a method of surface structure mesh generation in structural mesh automation.