Investigation of Heat Transfer to a Sharp Edged Flat Plate Using a Shock Tube.

The heat transfer mechanisms taking place in the flow induced behind an incident shock wave traveling across a flat plate were investigated. The boundary layer behind the shock is described by a transient boundary layer followed by a steady state boundary layer as the effects of the leading edge are transmitted down stream. The transition from laminar to turbulent can take place in either boundary layer. Limited data exists on the transition region. The use of a multichannel high speed transient data recorder allowed thin film heat transfer gauges six axial locations down the length of a sharp edged flat plate to be simultaneously sampled. From this the heat transfer rate history for each location was time correlated to the same flow conditions. The results indicate that the transition from laminar to turbulent flow is occurring from the unsteady region of the flow. The initiation of transition to turbulent flow occurs at successive gauge locations at the same time relative to the incident shock passing the gauge position. Limited evidence is presented which indicates that the leading edge may retard the initiation of transition at gauge locations close to the leading edge may retard the initiation of transition at gauge locations close to the leading edge if the steady Reynolds number for the flow behind the incident shock is in the laminar regime.