Turbulence Manipulation in Wall Jets
A wall jet is a flow phenomenon that has features of both a boundary layer and a jet. Its main application lies with turbine blade cooling and high lift airfoils or flaps. In the former case it is desirable to prevent the cooling- fluid from mixing with the ambient flow in order to keep the protective layer as far downstream as possible. Therefore the aim of this investigation is to influence the global characteristics of a turbulent wall jet, such as the spreading rate and the skin friction. This can be achieved by preventing the formation of large structures in the shear layer by disturbing the laminar shear layer in the vicinity of the nozzle of the wall jet. A thin circular cylinder in the spanwise direction can introduce such a disturbance which decreases the local half-width of the wall jet and increases the skin friction.