Large eddy simulations of supersonic flow over a cylinder using an immersed boundary method

Supersonic flow over a cylinder at Mach 3 is simulated to test and validate a curvilinear immersed boundary (CurvIB) method for high-speed flows. The CurvIB enables simulating flows with complex and moving boundaries, but it still needs to be further tested for high-speed turbulent flows. The canonical supersonic turbulent flow over the cylinder is chosen for this purpose. The convective terms are discretized with a hybrid scheme comprising a fourth-order central scheme and a third-order weighted essentially non-oscillatory (WENO) scheme. A switch function is incorporated to switch between WENO in the vicinity of shocks to central far away from shocks. It is found that the hybrid discretization can capture the instabilities in the shear layer as well as shock refraction, whereas using only WENO damped out the instabilities. Furthermore, it was found that the wall model greatly affects the separated wake and its reattachment behind the cylinder.