Research On Unstructured Boundary Layer Mesh Generation Technology For CFD Calculation Of Aircraft

With the rapid development of computer science and technology,computational fluid dynamics(CFD)has been applied in many practical projects in a revolutionary manner.As the preprocessing stage of CFD calculation,grid generation takes up most of the time in the whole process of numerical simulation.Boundary layer grid generation is an important part of the whole grid generation,which can capture the flow physical characteristics close to the surface more accurately.In the boundary layer close to the object surface,the technology of generating grids for complex geometric models is a difficult problem in actual engineering,and it has not been solved perfectly So far.Considering the accuracy of calculation and the adaptability of mesh,the boundary layer mesh in viscous flow is usually generated in the form of hybrid mesh.This kind of grid adopts flat semi-structured grid element close to the object surface,so its adaptability is the better.It is necessary to study the boundary layer grid generation method in viscous flow calculation,so as to improve the efficiency of grid generation,accuracy of grid calculation,adaptability of geometric shape and higher automation,so as to meet the application of CFD technology in practical engineering.In this paper,the unstructured boundary layer mesh generation method is studied in the following two aspects:(1)The radial basis function interpolation method and boundary layer mesh generation method are studied,and an unstructured boundary layer mesh generation technology is proposed.The main contents include: grid frame line extraction technology,boundary layer top-level mesh generation and unstructured grid point normal algorithm;(2)Based on the theoretical research of this paper and the NNW-Grid Star grid generation software platform,the unstructured boundary layer grid generation module has been developed.Using a typical aircraft model,unstructured surface grids are generated by NNW-Grid Star.The unstructured boundary layer grids of the model are generated by using the proposed method and the software pointwise respectively.Finally,the two grids are used to generate the external field grids and the numerical calculation is carried out.The reliability and superiority of the algorithm are verified quantitatively and qualitatively by statistical analysis of grid data and CFD numerical calculation data...