改善返回舱气动稳定特性数值计算研究

和第一宇宙速度载人再入飞行相比，以第二宇宙速度载人再入飞行对返回器的升阻比要求较高。文章给出了一种升阻比能够满足第二宇宙速度再入需求的返回器基本外形，分析了基本外形的气动性能以及质心位置对气动稳定特性的影响，结果表明基本外形在高超声速和亚声速下均存在第二静稳定配平点的问题。为了改善基本外形的气动稳定特性，文章提出了多种改进外形设计，包括增加稳定耳片、改变尾部外形设计等。通过数值模拟对这些改进外形的气动稳定性进行了分析，结果表明这些改进设计对于改善返回器的单点稳定特性是有效的。通过对流场特性的详细分析，对改进气动设计改善返回器稳定特性的机理进行了揭示和阐释。

Numerical Investigation of Improving Aerodynamic Stability Characteristics of a Reentry Capsule

The requirement for the L/D of a capsule configuration for manned reentry at the second cosmic speed is relatively high comparing to that of reentry flight at the first cosmic speed. A reentry capsule configuration with high L/D is proposed in this work. The basic configuration of the capsule is found to have a secondary statically stable trim point, which is highly undesirable since it would cause disastrous result once the vehicle flies at the secondary trim point during re-entry. In order to improve the aerodynamic stability characteristics in reasonable center of gravity range, a series of protuberance designs added to the basic configuration have been investigated. The numerical simulation results indicate that these designs are all effective in reducing the strength of the undesirable trim condition with reasonable location of center of gravity. The mechanism of the improvement in aerodynamic stability characteristics is revealed by analyzing the flowfield in detail.