An experiment on a cooled swept cylinder in a low-disturbance Mach 1.6 wind tunnel is described. The flow attachment line was disturbed by two- and three-dimensional roughness elements of varying size and the laminar/turbulent state of the boundary layer was determined with a hot wire. The results demonstrated that although cooling the wall increased the stability of the boundary layer, it promoted roughness induced transition. Analysis of the data suggested that the attachment-line Reynolds number could account for the effect of wall cooling if the viscosity was evaluated at a particular reference temperature. Three-dimensional trips proved more effective than two-dimensional trips in this low disturbance flow.
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