RELATION BETWEEN THE POINTS OF FLOW REATTACHMENT AND MAXIMUM HEAT-TRANSFER FOR REGIONS OF FLOW SEPARATION

The streamwise distribution of the Nusselt number within and just downstream of a region of flow separation displays a maximum whose location, relative to the point of reattachment of the flow, was investigated. Wind tunnel experiments were performed in which a circular cylinder was oriented longitudinal to a uniform freestream. Due to flow separation at the outer rim of the forward face of the cylinder, the upstream portion of the cylindrical surface was washed by a zone of recirculating fluid. Both the experimental and numerical results provided conclusive evidence that the commonly assumed equality of the points of flow reattachment and maximum heat transfer coefficient was, at best, a special case. For most of the cases investigated here, the heat transfer maximum occurred upstream of the reattachment point.