探测器对超音速刚性盘-缝-带型降落伞系统的影响

研究了流体初始马赫数为 2.0 时, 探测器的存在与否对刚性盘-缝-带型降落伞系统气动减速性能以及流场流体结构特性的影响. 对于非定常可压缩流体的数值模拟, 流场采用了三层块结构自适应网格加密技术, 配合混合形式的TCD (tuned center difference)和WENO (weighted essentially non-oscillatory)计算格式以及基于拉伸涡亚格子模型的大涡模拟方法来处理超音速流中的激波以及大尺度湍流旋涡结构等. 结果表明: 无探测器时, 降落伞系统的流场结构稳定, 扰动较小; 有探测器存在时, 探测器后端的湍流尾迹和伞衣内部逆向运动溢出的流体与伞衣前端的弓形激波周期性的相互作用, 使得激波位置发生前移、激波倾角变小, 伞衣内部流场难以达到平衡稳定状态. 这加剧了降落伞系统的气动阻力振荡脉动变化, 降低了降落伞系统气动阻力系数, 同时也使得降落伞系统流场尾迹结构更加复杂. 

INFLUENCE OF THE CAPSULE ON THE SUPERSONIC RIGID DISK-GAP-BAND PARACHUTE SYSTEM

The influence of aerodynamic deceleration performances and flow features of the rigid disk-gap-band parachute system at Mach 2.0 with/without the capsule was studied. For the numerical simulation of unsteady compressible fluid, it adopted the three-layer block-structured adaptive mesh refinement, and a hybrid TCD (tuned center difference) and WENO (weighted essentially non-oscillatory) algorithm and the large-eddy simulation method with the stretched-vortex sub-grid model were used to process the shock waves and large scale turbulence vortex in supersonic flow. The results show that, the flow structure of the parachute system is stable and the disturbance is small without the capsule; when the capsule exists, the periodic interaction between the turbulent wake behind the capsule and the reverse fluid from the inside of the canopy and the parachute shock wave, makes the position of the shock wave move forward and the angle of it become smaller. The flow flied inside the canopy is difficult to reach a stable state, which intensifies the aerodynamic drag oscillation of the parachute system. The aerodynamic drag coefficient of the parachute system is reduced, and the wake structure of the parachute system is more complicated.