Transonic flow instability in the entrance region of a channel with breaks of walls

We study numerically turbulent flow of the air in a channel with breaks of walls. The flow is supersonic downstream of the break section and in the free stream. Instability of shock waves formed in the channel and in front of the entrance is examined. Solutions of the Reynolds-averaged Navier–Stokes equations are obtained with a finite-volume solver of second-order accuracy. The solutions demonstrate an expulsion/swallowing of the shock waves with variation of the free-stream Mach number. Effects of the upper wall slopes on the shock wave positions and flow bifurcation are examined.