On the velocity profile of inclined jets in a boundary layer for vorticityproduction

The velocity profiles of air-jet vortex generators have been investigated, and the effect of varying velocity profiles on vortex production has been a ssessed. In the simplest case of a jet generated by fluid effusing through a cylindrical hole drilled into a solid surface, the internal flow in the n ozzle is critical to the development of jets to be used for vortex producti on. A series of Pitot traverses through a range of jet diameters and pitch angles has been made in order to characterize the jet development. In order to produce an axisymmetric jet profile, modifications were made to the jet nozzles, thereby overcoming the critical flow features within the jet nozz le. In order to assess the jets for vortex production, a range of air-jet vorte x generator configurations have been used to produce discrete vortices in a turbulent flat plate boundary layer. Velocity vectors were measured over a cross-stream plane through the vortices, from which the vorticity could be derived across the plane. The vorticity at the centre of the vortex (or th e peak vorticity) was then used as an indication of the strength of the vor tices. It has been shown that the nature of the jet velocity profile is not significant to the strength of the vortex, so long as the average jet velo city is held constant.