ADVANCES IN SHOCK TUBE EXPERIMENTAL INVESTIGATION FOR HIGH-SPEED INTERFACIAL FLOWS

Shock-induced fluid interfacial instability has wide applications in some major projects such as inertial confinement fusion and hypersonic technologies, and has significant scientific significance in aspects such as vortex dynamics, flow stability, and the formation mechanism of turbulence. The challenges of the relevant problem mainly lie in two aspects. On one side, the shock waves, referred to as strong discontinuous disturbance waves with a propagation speed greater than the speed of sound, have sudden changes in physical parameters such as velocity, temperature and pressure in the flow fields before and after them. On the other side, the fluid interface is an important source of flow complexity, and the intermittent physical quantities at the interface significantly intensify the changes in the flow structure and morphology. Existing studies have shown that shock tubes have unique advantages in the research of high-speed interfacial flow problems, and can provide experimental images with high spatiotemporal resolution and reliable basic data. Here, the controllable generation principles and methods of converging shock waves in shock tubes were reviewed first. The equipment structures and characteristics of horizontal and vertical annular coaxial shock tubes, semi-annular converging shock tubes, conical converging shock tubes and wedge-shaped converging shock tubes were introduced, respectively. Furthermore, the latest progresses in the experimental techniques and flow mechanisms of high-speed interfacial flow induced by strong shock waves were reported. The theoretical methods and reverse design principles for the continuously smooth curved pipe wall design of shock tubes were presented. The stability, reliability and repeatability of the high-intensity shock tube experimental system were verified experimentally. The data of complete wave system evolution and interface structure development during the shock wave propagation process were obtained, and the mechanisms of shock proximity and secondary compression effects on the nonlinear evolution of disturbances were clarified. Finally, the key issues and development trends faced by the experimental research on high-speed interfacial flows were prospected.