Research on numerical method of air flow around the high-speed train under crosswind using tetrahedron unstructured mesh

Abstract

Because of the ability to reveal the characteristics of fluid flow in detail, the numerical simulation method becomes more important in designing high-speed train parts with better aerodynamic performance, such as nose shape, lower-drag body and so on. Using a CFD code based on the finite volume method, the present study carried out numerical simulation of air flow around ICE2 high-speed train under crosswind. The SIMPLE algorism was used in solution of N-S equations of three dimensional, steady state and incompressible flow of fluid which possesses constant physical properties. Tetrahedron unstructured mesh was generated using ICEM CFD software. Comparison study of present work with a classical experimental research performed by overseas scholars shows that the results of solution method using QSKE turbulence model and MARS scheme is reliable. Thereafter, the grid independence research was performed in two ways, one is to fix the height of the first layer cells around the body but change the overall number of cells, and the other is to fix the overall number of cells but change the height of the first layer cells around the body. It is shown that the mesh with both the proper number of cells and the height of the first layer can produce better simulation results. The conclusion of present study could be used in further numerical study of high-speed train with rather complicated geometry.