| Hypersonic flight technique is developing at a fast speed nowadays,and dependence of the design for hypersonic vehicles on CFD is increasing,but numerical results are sensitive to factors such as spatial schemes,flux functions and grids,so evaluating the reliability of computational results has become an important part of CFD.Verification and validation studies are important tools and methods for evaluating new schemes,new methods as well as new models at present.In this paper,four typical hypersonic cases are chosen to carry out verification and validation studies,mainly investigating the influence of numerical factors such as spatial schemes,flux functions and grids on shock capturing,predictions of skin friction and aerodynamic force/heat,computations of flow separation and reattachment in hypersonic flows.Main work of this paper are as follows:Two dimensional inviscid supersonic flow over a bluntbody is numerically simulated to study the influences of spatial schemes,flux functions and grid density on convergence of computations,shock capturing characteristics,grid convergence of pressure ratio and total enthalpy.Two dimensional laminar hypersonic flow over a plate is numerically simulated to study the influences of mach number,spatial schemes,flux functions and grid renolds on predictions of skin friction,computations of velocity profiles and temperature profiles within the boundary layer.Verification of computational results is carried out by comparing skin friction,velocity and temperature profiles with Blasius solutions.Hypersonic flow over a cylinder-flare is numerically simulated to study the influences of spatial schemes,flux functions and grid density on grid convergence results,locations of flow separation and reattachment,accuracy of aerodynamic force/heat predictions.Validation of computational results is carried out by comparing aerodynamic force/heat with wind tunnel experimental data.Hypersonic flows over a double ellipsoid with an angle of attack ranging from-5° to 25° are numerically simulated to study the influences of spatial schemes on resolution of complex structures such as the second separation in flow fields and accuracy of aerodynamic force/heat predictions.Validation of computational results is carried out by comparing aerodynamic force/heat with wind tunnel experimental data.Through numerical simulations of the hypersonic cases above,advantages and disadvantages of high order WCNS and second order MUSCL in numerical simulations of hypersonic flows,and characteristics of Steger-Warming,Van Leer,AUSMPW+ and Hybrid Roe-Rusanov flux functions are analyzed and summarized. |
