Global instability of the interaction between an oblique shock and a laminar boundary layer

This study investigates the oblique shock-wave/boundary-layer interaction with a Mach number of 2.15 and Reynolds 1×105. Both global stability analysis direct numerical simulation are used to reveal instability characteristics three-dimensional details incident shock flow. The results indicate that stationary occurs when angle exceeds critical 31.8°. At equal 33°, an additional unstable mode appears, which is oscillatory at large wavelength gradually dominant decreases. As further reduced, its conjugation evolve into two modes different growth rates. A criterion for flow established based on triple deck theory, determines only through free-stream conditions angles. performed 32° case. It found secondary separation during nonlinear growth, absent in two-dimensional base Moreover, separated undergoes perturbation spanwise doubled structures change significantly. oscillates around quasi-steady state end, indicating can develop unsteadiness without external disturbances.