Wall-Pressure Fluctuations Induced by a Forward Step in a High-Reynolds-Number Turbulent Boundary Layer

Wall-modeled large-eddy simulation is employed to compute wall-pressure fluctuations induced by a small forward-facing step immersed in a high-Reynolds-number turbulent boundary layer at momentum-thickness Reynolds number of 15,500 and step-height Reynolds number of 26,600. The results are compared with multiple experimental measurements at comparable step-height Reynolds numbers. The step drastically amplifies pressure fluctuations in the downstream. Consistent with most previous experimental and numerical results, the maximum pressure fluctuations occur slightly before the reattachment point on the upper surface, and the spectral level at low frequencies increases by more than two decades compared with that of the unperturbed boundary layer. The numerical results are in agreement with most experimental data with notable exceptions. They are shown to be grid converged, domain-size insensitive, and with negligible blockage effect.