"A Study on Shock Wave Self-Excited Oscillation in Supersonic Flows"

本文研究了超声速流中激波自激振荡现象。因此，许多超声速流与激波已被实验和计算研究。重点是基于对超音速流中激波自激振荡的流动结构和流动物理的物理理解。在本研究中，为研究项目选择了以下八个主题并进行了研究，本研究的目标已经完成。（1）研究了激波/湍流边界层中激波的自激振荡。流动分离是不均匀的，非常不稳定。非定常特性与马赫数无关。采用激光诱导荧光（LIF）流动显示技术测量密度等值线. (2)本文研究了超声速对向喷流中激波的自激振荡。数值模拟结果与实验结果吻合较好。Measu 关于我们 红色压力波动表明，由于射流的总压力，主频率发生变化。(3)研究了超声速射流与壁面的干扰流场。由于喷嘴出口与壁面之间的距离不同，干扰流态和激波振荡态发生了剧烈的变化。(4)研究了超声速混合流场。数值模拟也进行了相当好的协议与实验。提出了超音速混合的新技术，并证明了它的能力。(5)在热、化学非平衡条件下研究了激波诱导的气动加热。高温对气动加热的影响已被揭示。(6)本文研究了钝头体前激波产生的气动激励问题。气膜冷却已被证明有足够的能力，以减少气动加热。(7)研究了再入飞行器翼面差距产生的空腔流动，给出了峰值压力和峰值加热。捕获了含嵌入激波的振荡空腔流。(8)研究了塞式喷管超声速嵌入激波绕流。研究了塞式喷管形状对阻力的影响，通过优化喷管形状，获得了大幅度降低阻力的效果。少

The purpose of the present study is to investigate the shock wave self-excited oscillation in supersonic flows. Hence, many supersonic flows with shock waves have been experimentally and computationally studied. The emphasis is based on the physical understanding of the flow structure and flow physics of shock wave self-excited oscillation in supersonic flows. For the research projects eight topics are selected and studied in the present study as follows and the objectives of the present study have been completed. :(1) Self-induced oscillation of shock wave in shock wave/turbulent boundary layer have been studied. The flow separation is not uniform and quite unsteady. Also the unsteady features are independent on mach number. The new flow visualization technique by LIF is installed for the measurement of density contour.(2) Self-induced oscillation of shock wave in opposing jet in supersonic flow have been studied. Numerical simulations show quite good agreement with experiments. Measu … More red pressure fluctuations show that dominant frequency changes due to total pressure of jet.(3) Interacting flow field between supersonic jet and wall has been studied. The interacting flow pattern and shock wave oscillation pattern changes drastically due to the distance between the nozzle exit and wall.(4) The supersonic mixing flow fields have been studied. Numerical simulations have been also conducted resulting quite good agreement with experiments. The new technique for supersonic mixing has been proposed and demonstrated its capability.(5) Shock wave induced aerodynamic heating has been studied with thermally and chemically nonequilibrium conditions. High temperature effects on aerodynamic heating have been revealed.(6) Aerodynamic haeting problems generated from shock wave ahead of the blunt body have been studied. Film cooling has proved to have sufficient capability for reducing aerodynamic heating.(7) Cavity flow generated by the gap of the tile of the reentry vehicle has been studied with peak pressure and peak heating. Oscillatory cavity flows with embedded shock waves have been captured.(8) Supersonic flows with embedded shock wave around plug nozzle have been studied. The effect of the shape of plug nozzle on the drag is investigated and the drastic reduction of the drag is obtained by optimal nozzle shape. Less