The Analysis of Interaction Between Reflected Shock Wave and Boundary Layers in a Shock Tube

This study is a computational investigation of the interference between a reflected shock wave and the wall boundary layers formed by gas flow in a shock tube. Two gases, namely, Argon and Helium, are examined as the working fluid in each case at different pressure ratios. The present computations consider the viscous effects and implement turbulence through the Spalart-Allmaras model. The study observes and analyzes the non-ideal transient behavior in the shock tube. It also examines thermal effects and the shock bifurcation for two gases at different pressure ratios of 10 and 100. The present simulations explain the temperature distribution behind the bifurcated shock waves. The results show that the range of disturbance formation for each gas varies with pressure ratio. The outcomes of this study agree well with theoretical methods, which assume uniformity behind the reflected shock wave under ideal conditions. However, consistent with the past studies, this investigation confirms that reflected shock waves interact with the wall boundary layers, and bifurcation occurs. We noticed the gas pressure ratio plays a significant contribution to the tendency and strength of the bifurcation. The higher the pressure ratio, the faster the shock wave traveled, and the quicker the relative bifurcated foot velocities increased with the Mach number at that region. This research contributes and sheds light on the role of gas type and other parameters on the nature of the interaction between a traveling shock wave and a thin boundary layer. This investigation’s findings will benefit the supersonic compressible flow applications and experiments.