TVD格式与高超音速气动加热数值模拟

为了在化学非平衡流动中获得准确的流场解以及表面热流分布,将总变差减小TVD(Total Variation Diminishing)格式中的熵修正函数,由各向同性分布改为各向异性分布,同时让熵修正函数中的参数与流场中的压力梯度分布相关.将改进后的熵修正函数运用到高超音速化学非平衡绕流流场的数值模拟中,获得了较使用原有熵修正函数更为准确的流场参数和表面热流分布.采用改进的熵修正函数,可以提高壁面附近的粘性分辨率,降低热流计算结果对壁面附近法向网格尺度的敏感性. 

TVD scheme and numerical simulation of aerodynamic heating in hypersonic flows

In order to get more accuracy results for heat transfer in chemical non-equilibrium hypersonic flow simulations,a new entropy correction function in TVD(total variation diminishing) scheme was presented.By study of characters of the flow in boundary layer,an anisotropy entropy correction function was used in the TVD scheme instead of the isotropy entropy one,the new coefficient in the entropy correction function,which is varied according to the distribution of the pressure in the flow field,was adopted.The numerical test of the chemical non-equilibrium hypersonic flows over sphere verifies the new entropy correction function.The flow field and the surface heat transfer rate were obtained by the numerical simulation.The results show that the new entropy correction function can improve the accuracy of surface heat transfer as well as the flow field in numerical simulations.The new entropy correction function can also improve viscosity resolution near the surface.The surface heat transfer rate,which is calculated by using new entropy correction function,is less sensitive to the size of grid in normal direction near the surface.