论文标题

高度稀释的气流在椭圆上

Highly dilute gas flows over an ellipse

论文作者

Cai, Shiying, Cai, Chunpei, Li, Jun

论文摘要

本文通过使用煤气理论,提出了最新的研究结果,该研究结果是对散布或触发反射椭圆的自由流动的结果。引入了沿A扩散反射表面的虚拟密度分布以帮助研究。获得许多局部表面特性,包括表面滑动速度,压力,摩擦和热通量的系数。还通过整合局部表面分布来获得空气动力和力矩的全球系数,质量中心中心距离。最后,还获得了漫射场或镜面反射椭圆周围流动场的分析表达式。特殊的非参数(例如温度和速度比)明确嵌入这些表达式中。使用直接模拟蒙特卡洛(DSMC)方法进行粒子模拟,以验证上述结果。这些表达式需要计算机进行评估,但是,与DSMC模拟相比,成本非常小。这些方法是启发式调查其他无碰撞流动的启发式方法,并且可以将载荷系数视为基线参考,处于高knudsen数字限制。在椭圆上进一步研究稀疏的气流量较少是可行的。基于这些解决方案的Swift参数研究是可行的,可以研究其影响。

This paper presents recent investigation results on free molecular flows over a diffusely or specularly reflective ellipse, by using the gaskinetic theory. A virtual density distribution along the a diffusely reflective surface is introduced to aid the investigations. Many local surface properties are obtained, including surface slip velocity, coefficients for pressure, friction, and heat flux. Global coefficients for aerodynamic forces and moments, mass center-force center distances, are also obtained by integrating the local surface distributions. In the end, analytical expressions for the flowfields around a diffusely or a specularly reflective ellipse are also obtained. Special non-parameters, such as temperature and speed ratios, are explicitly embedded in these expressions. Particle simulations with the direct simulation Monte Carlo (DSMC) method are performed to validate the above results. Those expressions need computers for evaluations, however, the cost is very minor when compared with DSMC simulations. The approaches are heuristic to investigate other external collisionless flows, and the load coefficients can be considered as baseline references at the high Knudsen number limit. It is feasible to further study less rarefied gas flows over an ellipse. Swift parameter studies based on these solutions are feasible to study their influences.

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