Effect Of Grid Strategy On Numerical Simulation Results Of Aerothermal Heating Loads Over Hypersonic Vehicle

Hypersonic vehicle technology has become one of research hotspots among powerful countries in aerospace research,and the numerical prediction accuracy of surface heat flux over complex hypersonic vehicle is one of the core problems restricting the development of hypersonic vehicle.The accuracy prediction of surface heat flux is affected by grid strategy,numerical discretization method and other factors,and there is some uncertainty in the selection of grid metric.Therefore,a grid generation method was proposed in this paper,and the applicability of this method was verified by numerical simulations.Firstly,applying theoretical analysis and numerical simulation a grid generation method is proposed according to cell Reynolds number and freestream Reynolds number based on wall parameters and characteristic length of bluff body respectively,and reference value range of cell Reynolds number based on wall parameters was also provided for the numerical simulation of laminar flow around hypersonic blunt body.The proposed grid generation method was then applied to simulate hypersonic aeroheating computations over semi-cylinders and semi-spheres at different incoming flow conditions.The results show that the proposed grid generation method and the suggested range of the cell Reynolds number based on wall parameters can satisfy the precision requirement of thermal environment simulation over hypersonic bluff bodies,and the rational distribution of grids and can also improve the efficiency of numerical calculations simultaneously.Secondly,for the numerical simulation of hypersonic transitional and turbulent flow over cones,another grid generation method of determining grid metric for transitional and turbulent region by combining y+ and transitional Reynolds number was proposed by applying theoretical analysis and numerical simulations.Using the proposed grid generation method,the heat flux over the conical surface at different inflow conditions was then simulated.The results show that the proposed grid generation method can satisfy the precision requirement of thermal environment simulation over the hypersonic cones,and the rational distribution of grids and can also improve the efficiency of numerical calculations simultaneously.Thirdly,in order to verify the mesh generation method proposed in this paper further,numerical simulations of surface heat flux over complex vehicle considering laminar,transitional and turbulent flows,lifting-like vehicle was selected for verifications,and the influence of incoming flow parameters and the wall temperature on the surface heat flux and boundary layer transition was preliminarily studied over the lifting-like vehicle.The results show that the proposed grid generation method can satisfy the precision requirement of thermal environment simulations at laminar,transition and turbulent regions over hypersonic lifting-like vehicle.Finally,a brief summary of the full thesis and directions for further research was given.