Parametric Design Of High Speed Train Head Based On Partial Differential Equation

In recent years,with the continuous development and expansion of high-speed railways,the operation speed of high-speed trains has been continuously improved.Because of the close relationship between the aerodynamic performance of the train and the shape of the train head,the combination of parametric train geometry model and computational fluid dynamics simulation using optimization algorithm is a new direction of high-speed train design research.The existing parametric geometric models of high-speed trains are characterized by a large number of design variables and complex model descriptions.and the increase of design variables makes the calculation of computational fluid dynamics increase into geometric series,which is unbearable in engineering.In the past ten years,the Partial Differential Equation(PDE)modeling method has been applied to the field of computer-aided design as a new and efficient surface modeling tool.This method can be used to solve the construction of transition surface,the surface interaction design and other aspects of the problem.In this paper,the parametric modeling method of partial differential equations is introduced into the parametric design of the train head shape,and a new parameterized train head is generated by this method.In this paper,the head shape of the high-speed train is divided into 17 patches,then the partial differential equation corresponding to each patch is solved by the finite difference numerical method,and the solution of the partial differential equation is used to approach the divided patch,and at the same time,the parameterized PDE patch of high-speed train head is also obtained.A new type of parameterized train head with grid information can be obtained by stitching all the PDE patches together and using the mesh generation technology of reverse engineering software Geomagic.Since a boundary edge and a boundary tangent are shared between adjacent patches,the joint between the them is smooth,which satisfies the core design concept of the streamline type of the train head.At the same time,a high-speed train head shape parametric design system based on partial differential equation(PDE)is developed.The user can control the shape of the train head shape by adjusting the value of the design parameters to generate new high-speed train head shapes of different shapes.