抄録
Boundary layer separation occurs in the region where the adverse pressure gradient exists because of reducing the momentum of fluid by viscous action near the solid surface. To prevent the separation we transport the momentum of a freestream to a boundary layer with longitudinal vortices generated by the interaction between freestream and jet flow. We studied for three kinds of jet orifice. Those are square and two kinds of rectangles. The aspect ratios of rectangles are both 6.4 but their long sides are set in streamwise direction or in spanwise direction. We measured three-dimensional velocities and calculated secondary flow vectors and vorticities. As a result, the vortices generated by the spanwise orifice are strongest among all the orifice shapes and their positions are nearest to the lower wall. It was found that shape differences among the jet orifices produce longitudinal vortices of different strength and of different distance from the lower wall. Therefore the case with spanwise orifices is most effective on the boundary layer separation control.
