可压缩流向涡与反向运动激波相互作用的实验

AN EXPERIMENTAL INVESTIGATION ON INTERACTION OF A COMPRESSIBLE STREAMWISE VORTEX WITH A MOVING SHOCK WAVE 1)

对可压缩流向涡与反向运动激波相互作用的现象进行了实验研究．实验在９４ｍｍ×９４ｍｍ的方截面激波管中进行．在实验段上游安装了一个有限翼展平直机翼．当入射激波通过机翼后，波后２区气流在模型翼尖诱导出一条流向涡．入射激波在激波管端壁反射后，形成的反射激波在观察窗处和流向涡发生作用．实验中拍摄了激波与流向涡作用全过程的纹影照片，观察到了一些和定常激波与旋涡相互作用不同的现象，并与数值计算结果进行了初步比较．

An experiment on the interaction of a compressible streamwise vortex with a moving shock wave has been conducted in a shock tube with 94 mm×94 mm square cross section. A finite span wing was mounted in upstream of the test section. When a shock wave passed through the wing, a streamwise vortex was induced from the tip of the wing by the supersonic flow behind the shock wave. After the incident shock wave reflected from the end of the shock tube, the interaction of the reflected shock wave with the streamwise vortex occurred at the position of the viewing window. A series of schlieren pictures were taken in the experiments. Some phenomena different from that of steady interaction were observed. It showed that in the incipient stage of the interaction the shock front decomposed slightly and the vortex core distorted to a spiral shape. As time passed, the size of the decomposed bubble shock became larger and a recirculation bubble appeared downstream of the shock front. The vortex core disappeared in the recirculation region and reconstructed downstream of it. A Mach stem like shockwave was found at the joint position of the bubble shock and the incident shock. Also some waves which were not axial symmetric with respect to the undistorted vortex core were observed in the bubble shock. The numerical investigation was also carried out to simulate the interaction. The Euler equation was used under the quasi axissymmetric assumption. The upwind TVD scheme was implemented. With the total enthalpy constant and zero radial velocity assumption as well as the given profile of the tangential velocity of the vortex, the radial momentum equation was integerated to get the presure and density profile. The numerical result showed the waves observed in the experiment. Further Navier Stokes simulation will be carried out.