Transition Control via Boundary Layer Heating

Abstract : This Report describes a theoretical method, based on linear stability theory, for predicting flow transition on axisymmetric heated underwater bodies, and a simple experiment using a four-to-one ellipsoidal nose in the 30-inch Water Tunnel. The experiment showed that filtering the tunnel water and vibration of the model have an effect on transition. Agreement between theory and experiment is good without heating, but a more sophisticated experiment is needed to validate the theory for heated bodies. Although increases in transition Reynolds number of 40 per cent were observed experimentally, the theory suggests that much greater increases are possible for the same heat input by distributing it differently over the body surface. Keywords: Convective heat transfer, Boundary layer control, Boundary layer transition, Flow measurement, Axisymmetric bodies, Great Britain.