Thermal-control technique to improve flow characteristics over curved and rotating surfaces

One of the particular features of flows with available large-scale vortices deals with specific mechanisms of fluid transport. Thus modifying vortex scales, one can affect processes of heat and momentum transfer near a wall. In this connection, experiments were carried out to demonstrate how a scale of a fluid motion can be changed both in transitional and turbulent boundary layers using an imposed spanwise-regular temperature distribution over the surface. This method was tested for flows under body forces where counter-rotating streamwise vortices are an inherent flow feature. An active mode of vortex generation is realized due to two independent variables, spanwise scale of induced vortices and temperature gradient over the surface that can be adjusted to current flow conditions. Velocity fields and spectrum redistribution in boundary layers with embedded streamwise vortices show efficiency and prospects of the proposed method to control turbulent transport.