再人体复杂外形无粘流场数值计算研究

STUDY OF NUMERICAL COMPUTATION OF INVISCID FLOW FIELD ABOUT COMPLEX CONFIGURATION OF RE-ENTRY VEHICLE

本文在文[1,2,3]的基础上研究了非定常Euler方程的推进迭代方法,并将无波动、无自由参数的耗散差分格式(下称NND格式)发展为隐式、迎风格式,用以计算有差曲控制翼的再入复杂飞行器的育攻角、有侧滑角的超声速无粘绕流流场。其结果是准确的。本文的方法具有以下特点: 1.可以在同一计算程序中实现亚跨超流场的计算:在超声速区域,采用推进技术;在亚跨声速区,则自动选择推进迭代求解技术。 2.NND格式不仅具有公式简单,无自由参数的特点,而且过激波时满足熵条件,不会产生非物理解,也不发生振荡。 3.隐式差分格式的无条件稳定和Gauss-Seidel迭代的快速收敛,计算省时。 本文的方法曾用于烧蚀头部凹陷外形和航天飞机简化外形的计算,能自动选择迭代和推进区域。可以预言,如计算机条件许可,本方法可以用于大攻角的无粘流场计算。

In this paper we have studied marching and iterating method to solve unsteady Euler equations on basis of these papers, and have developed non-oscillatory containing no free parameter dissi-pative scheme ( NND scheme) into implicit upwind scheme. This scheme is used to calculate inviscid supersonic flow around complex re-entry vehicle containing controlling wings with the angle of attack and the side-slip angle. The numerical results are accurate. The method in this paper has the following specific properties.1. The calculation of subsonic, transonic and supersonic flow field is achieved with the same program. Marching technique is adopted in supersonic flow region, and iterating technique is used automatically in subsonic and transonic flow regions.2. NND scheme is simple and contains no free parameter. In addition, the scheme satisfy entropy condition. So the results of computation can avoid numerical oscillations.3. This method needs less computing time due to the unconditional stability of implicit scheme and the fast convergence of Gauss-Seidel iteration.This method has been used to compute flow field about dented configuration of burnt forebody and about modified configuration of space shuttle. In calculation, the method automatically decides marching and iterating regions, is expected that this method can be applied to the computation of inviscid flow with large angle of attack if the condition of computer is good enough.