Effect of streak employing control of oblique-breakdown in a supersonic boundary layer with weak wall heating/cooling

Official URL: https://dx.doi.org/10.1103/PhysRevFluids.7.053904

Contrary to incompressible flows, there has been an immense research gap in the flow transition control using velocity streaks for supersonic flows. The first direct numerical simulations (DNS) study in this direction was conducted at Mach 2.0 for an adiabatic wall condition and showed that effective control could be provided by employing streak modes having four to five times the fundamental wave number of the most amplified oblique disturbance waves. However, the application range of the method in terms of the control amplitude is studied roughly and only for adiabatic walls. The present study scrutinizes the controlling capability of these decaying streak modes under the influence of both adiabatic and weak wall heating/cooling by means of DNS. The stabilizing/destabilizing influence of the control streaks in combination with different thermal boundary conditions in a perturbed boundary layer is shown. The effective range of the streak amplitudes under the given flow conditions is presented both for adiabatic and isothermal wall conditions. No significant impact of the wall-boundary condition on the control-streak development is observed in the sustainable flow control range, but the useful control-streak amplitude range diminishes with wall heating.