Compressible Large-Eddy Simulation of Separation Control on a Wall-Mounted Hump

Abstract

Compressible large-eddy simulations of turbulent flow over a wall-mounted hump with active flow control are
\nperformed and compared with previous experiments. The flow is characterized by the unsteady separation before the
\nsteep trailing edge, which naturally reattaches downstream of the hump to form an unsteady turbulent separation
\nbubble. The low Mach number large-eddy simulation demonstrated a good prediction of surface pressure coefficient,
\nseparation-bubble length, and velocity profiles compared with experiments. The effect of compressibility on the
\nbaseline flow is documented and analyzed and is found to increase the separation-bubble size, due to a reduced
\ngrowth rate. Control is applied just before the natural separation point via steady suction and zero-net-mass-flux
\noscillatory forcing, and steady suction is shown to be more effective in decreasing the size of the separation bubble and
\npressure drag for the control parameters investigated. Controlled flow at a compressible subsonic Mach number is
\napplied, and found to be slightly less effective than the same control parameters at low Mach numbers.