高超声速双锥体绕流的数值计算与流场分析

 双锥几何外型的高超声速绕流问题涉及激波-激波相互干扰以及激波-边界层相互作用等复杂流动现象，是计算流体力学领域的热点问题，常被作为此类复杂流动的典型算例。本文从守恒型Navier-Stokes方程组出发，考虑了非平衡态气体的振动激发过程，采用高分辨率TVD有限差分格式研究了5种来流马赫数（15.56，10.34，9.59，8.20和8.06），2种气体环境（纯N2和纯O2），以及2种双锥外型（尖头体和钝头体）的气动热力学特性，较详细地给出了上述各种情况下壁面热流密度分布以及气动力系数等重要参数，所得结果与国外相关实验数据吻合较好，初步显示了本文所编程序的有效性。对差分格式精度和典型限制器（minmod、van Leer限制器）进行比较，发现数值计算所得分离区大小受格式耗散性影响很大，其中使用van Leer限制器所得到的分离区大小与实验结果吻合得较好。

Numerical Computation and Flowfield Analysis of Hypersonic Flow over a Double-Cone Body

In recent years, numerous studies about shock/boundary layers and shock/shock interactions in hypersonic flow over a double-cone body were reported. The interaction between a shock wave and a separation zone in a hypersonic flow is a very challenging problem because of its complexity. Previous researches show that the heat transfer rate on the cone forebody is over-predicted by about 20% and the separation zone is slightly too large. The hypersonic flow over 25°～55° sharp double-cones and the blunt double-cone models are simulated by using the Navier-Stokes equations in the conservation integral form with multi-species and non-equilibrium molecular thermal excitation and chemical reactions. The cases presented in this paper include 5 different Mach numbers, which are 15.56, 10.34, 9.59, 8.20 and 8.06, respectively. The surface pressure and the heat transfer rate are obtained, with a good agreement between the continuum CFD simulations and experiments. A preliminary analysis of the effects of the numerical schemes on the simulation of the flow is also presented. It is shown that the simulation results, especially, the size of the separation zone, are very sensitive to the limiter used. The more dissipative limiters tend to reduce the separation zone size. The Roe scheme with van Leer limiter gives the most satisfactory results. The simulation of double-cone flows at high enthalpy in the environment of pure oxygen is also presented.