Numerical and Experimental Investigations on Mach 2 and 4 Pseudo-Shock Waves in a Square Duct

摘要

The structures and characteristics of λ-shaped and X-shaped pseudo-shocks in a square duct are investigated through numerical simulations and experiments at Mach 2 and Mach 4, respectively. The experiments were carried out in a pressure-vacuum supersonic wind tunnel with a test cross section of 80 x 80mm~2. Numerical simulations were carried out using the Harten-Yee second-order TVD scheme and the Baldwin-Lomax turbulence model. The Reynolds numbers for the Mach 2 and 4 cases were Re_∞ = 2.53 x 10~7 and Re_∞ = 2.36 x 10~7, respectively, and the flow confinement was δ_∞/h = 0.35 for both cases. The computational results for the Mach 2 pseudo-shock wave are in good agreement with the experimental results. Based on this agreement, the flow quantities, which are very difficult to obtain experimentally, were analyzed by numerical simulation. Although several differences were found between the computational results and experiments in the case of Mach 4 due to asymmetric characteristics in experiment which could not be reproduced in numerical simulation, the computational results are valuable for understanding this complex asymmetric phenomenon.