RÉSUMÉ

Particle Image Velocimetry (PIV) flow visualization measurements are performed in the efflux jet-stream field to determine the functions of slit flows coexisting with the flip-flop flow which generates multiple jet-flow groups of uniform flow rate accompanied by self-sustained oscillations. Various arrangements are tested with different ways of attaching the slit flows with the flip-flop flow unit. It is disclosed that flow shear induced by the slit-flow streams stretches the longitudinal vortices which are generated in the flip-flop flow in the flow direction. As a result, the efflux flow stream elongates in the flow direction and simultaneously suppresses flow velocity reduction. The functions are useful in the creation and elongation of air curtains.