Abstract
The vortex generator jets (VGJs) method can control flowfields or especially suppress flow separations in a wide range of conditions. The experiments were conducted using a low speed wind tunnel with a two-dimensional diffuser. To make better separation control we investigated the effect of jet orifice shape. Orifices of square shape were investigated instead of circular ones. Vorticity distributions and the static pressure in the divergent portion of the wind tunnel were measured. Pressure recovery was improved a little for square orifices at a certain pitch angle. At the angle, 45deg., for square orifices, we can keep the negative vortices near wall. However we found that the effect depends heavily on the pitch angle of jets than on the orifice shape.