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Abstract

The turbulent transonic flow over a wall with an expansion corner and ramp is studied numerically at free-stream Mach numbers from 1.11 to 1.28. A shock wave forms in front of a horizontal plate or bar located above the ramp. Solutions of the Reynolds-averaged Navier-Stokes equations are obtained on fine meshes with a finite-volume solver of second-order accuracy. The solutions demonstrate instability of the shock position at certain free-stream Mach numbers, which depend on the stream wise location of the plate/bar with respect to the ramp. The flow behavior under steady and unsteady perturbations in the free stream is analyzed. Also positions of the shock as functions of the ramp slope are studied.