隔离段激波串精细结构与压力特性实验研究

在马赫数为2.5的等截面隔离段风洞中开展了无控制和安装T形涡流发生器两种情况的瞬态流场结构显示与压力测量的实验研究。运用常规纹影和基于纳米示踪的平面激光散射技术（NPLS）对两种不同状态的隔离段激波串三维流场精细结构进行了显示测量。结果表明:较传统纹影的测量结构而言，NPLS精细测量能够得到湍流边界层、激波串、分离区等细节结构。T形涡流发生器产生的展向涡与激波串相互作用，激波串前缘结构为分叉正激波，紧跟其后的第二道激波实际上结构与其类似。同时采用高频压力传感器对两种隔离段中激波串的壁面压力进行了测量，采用常规统计分析方法和差分平方累和方法对激波串压力分布、脉动及其上传特性进行了分析。分析表明，差分平方累和方法可以有效检测激波串的前缘位置。

Experimental study on the fine structures and pressure characteristic of the shock train in the isolator

Experimental studies on the fine structures of the transient flow and the pressure measurement of the shock train in a constant area isolator with T-control and without controlling method are performed. To study the three dimensional structure of the shock train, the oriented schlieren technique and the nano-tracer planar laser scattering(NPLS) technique are used. The flow visualization results show that these two techniques can obtain the flow structures. Compared with the oriented schlieren, the NPLS technique can catch the fine structures of the flow such as the boundary layer of the turbulence, fine structures of the shock train and the separation area. With the interaction of shock train and vortex induced by the T shaped generator, the shock train edge is bifurcated and closely followed by the second similar structure. High frequency pressure measurements are conducted to reveal the shock train movement and its frequency-domain feature. The shock train location and its movements are detected by conventional statistical methods and the approach of pressure derivative integral. It is revealed that the approach of pressure derivative integral can detect the shock train arriving effectively.