Experimental investigation of a supersonic backward facing step flow

The flow over a backward facing step is investigated by means of infrared thermography. An inverse heat transfer procedure is used to calculate the surface heat flux from the measured surface temperature in time by taking into account multi-dimensional and unsteady conduction effects. Additionally schlieren visualization is used to get an overview of the flow field. The backward facing step flow is investigated for laminar, transitional and turbulent separating boundary layers. It is found that for the laminar and transitional cases the Stanton number and normalized separation length are influenced by the step height. For turbulent separation this is only marginally the case however the Stanton number downstream of reattachment increases with step height. For the transitional separation, large heat transfer peaks are measured at reattachment.