Study on Supersonic Jet Interaction

超音速射流干扰发生在火箭发动机的集束喷管中，以及羽流与地面和发射器以及与航天器本身的撞击中。本研究的目的是研究这种复杂的流场实验流动显示和密度测量使用瑞利光散射。利用激光诱导荧光技术进行了流动可视化，使流动在任意截面上可视化，并区分流动结构，如激波和气体界面。由于瑞利散射的强度与气体密度成正比，并且可以在任意点测量，因此建立这样的密度测量系统对于研究由相互作用产生的复杂流场，特别是稀薄气体流场具有重要意义。在本研究中，进行了以下研究：1。与超音速流相反的音速喷流排气的显示。2.超音速射流与垂直于射流轴线放置的平板相互作用的显示和密度测量。3.环形喷嘴径向欠膨胀射流的可视化和密度测量。通过这些研究，为复杂稀薄气体流动的可视化和密度测量提供了有效的方法。

Supersonic jet interaction occurs in a cluster nozzle of a rocket motor, and in plume impingement with the ground and the launcher, and with the space vehicle itself. The purpose of the present study is to investigate such complex flow-fields experimentally by flow visualization and density measurement using Rayleigh light scattering. The flow visualization was made using laser induced fluorescence, which enable to visualize a flow at an arbitrary cross section and to distinguish the flow structure such as shocks and gas interfaces. Since intensity of the Rayleigh scattering is proportional to the gas density and the measurement of the intensity can be made at an arbitrary point, establishment of such a density measurement system is important in investigation of complicated flow fields produced by interaction, especially in rarefied gas flows. In the present study, the following studies were made; 1. Visualization of sonic jets exhausting counter to a supersonic stream. 2. Visualization and density measurement of supersonic jets interacting with a plate placed at a right angle with the jet axis. 3. Visulaization and density measurement of a radially directed underexpanded jet from a ring-shaped nozzle. Through these studies the useful methods for visualization and density measurement for complicated and rarefied gas flows were established.