Unsteady flow around a concave body in supersonic flow

当高速飞行器进入地球大气层时，需要采用各种方法进行减速。降落伞是最有效的空气动力学减速系统之一，在体积可以很小，阻力肯定可以施加的情况下，降落伞已经被使用。但其柔性是一种非常复杂的现象，本研究主要采用数值模拟的方法来分析其流场特性。用TVD格式求解了三维非定常全N-S方程。用摆的运动方程分析了弹体的摆动，指出了降落伞对凹体流体与激波干扰的重要性，并指出了波状分布激波的早期发展。指出了虚拟质量对流场的重要影响、振动体与尾流的非线性相互作用等，在不久的将来，降落伞充气过程和流场的发展都需要完美地同时解决，表现出很强的非线性。在捕捉到这些现象后，我们可以提出准确的数据来设计新型降落伞。

It is necessary to decelerate by using various methods when the high speed vehicle entry into the atmosphere of the planet. One of the most effective, aerodynamic deceleration systems is the parachute, and has been used in the point that volume could be small, and that the drag can certainly applied. But, it is a very complex phenomenon for flexibility of it.In this research, the numerical simulation is applied mainly to analyze the feature of flow field. The 3-dimensional unsteady full Navier-Stokes equations are solved by using the TVD scheme. Also, the body oscillation is analyzed by the equation of the pendulum motion.The parachute would be pointed out the feature of the importance of the interference with "Overflow" of the fluid from the concave body and the shock wave, while the development of the wavy distributed shock wave is pointed out in early stage, too. Moreover, the important effect of the virtual mass on the flow field, the non-linear interaction of the oscillating body and the wake flow and so on are pointed out.In the near future, both the inflating process of the parachute and the development of the flow field should be solved simultaneously in perfect, which shows the very strong non-linearity. After catching the phenomena, we could propose the accurate data to design the new parachute.