Research On The Improvement In Elasticitybased Dynamic Mesh Method And Preliminary Application For Unsteady Flow Simulation Of Body Flap In Hypersonic Vehicle

The dynamic mesh is a key technique to deal with the unsteady flow problems involving moving boundaries,which is widely used in the problem of the variable geometry aircraft,the aeroelasticity and the fluid-structure interaction.Based on the classical elasticity-based dynamic mesh method,this paper has developed a variety of improved methods with higher quality and stronger robustness,and made research and application according to the unsteady problem of body flap in hypersonic vehicle.First of all,the characteristics and relative merits of three classical dynamic mesh deformation methods are compared and studied.The basic ideas and methods of spring analogy method,radial basis functions method and elasticity-based method are introduced in detail.The comparison and analysis are carried out from the aspects of maximum deformation capacity,mesh quality and mesh deformation efficiency.Summarizes the elasticity-based method application strategy in particular,providing guidance for engineering applications.Secondly,based on the classical nonlinear elasticity-based dynamic mesh method,some improved methods are proposed to increase robustness from the combination of classic methods,mesh quality feedback and local elastic modulus constraint.What’s more,the combined effect study of improved methods puts forward the most superior improvement scheme.Then,the improved elasticity-based method was validated through typical unsteady flow problems,such as NACA0012 airfoil pitching,plunging oscillation,three-dimensional ONERA M6 wing pitching and three-dimensional elastic plate vibration.The results show that the proposed method has good reliability and stability,and can be used for the numerical simulation of unsteady flow field.Finally,based on improved elasticity-based method,this paper has realized the deflection of body flap in hypersonic vehicle,analysized the dynamic changes of aerodynamic properites,flow pressure and surface states of body flap in unsteady flow field,and provided a basis to explore the aerodynamic-thermoelastic coupling problem of body flap.This thesis is about the research of high quality dynamic mesh technology,in view of elasticity-based dynamic mesh developed many kinds of effective improved methods.These methods are verified with high reliability and applicability,and can support for the simulation of body flap in hypersonic vehicle and other unsteady problems.