Abstract
Active control of rectangular jet has been attempted to manipulate the vortex shedding interval in the major shear layer. We observed vortex structure produced in an excited jet issuing from the nozzle of aspect ratio of 15. Jet characteristics strongly depend on the vortex structure in the shear layer. It was remarkably observed that the jet spreads more widely in the minor direction and shrinks more greatly in the major direction by the asymmetric excitation than that of the natural jet and by the symmetric excitation. The flow deformation process is clarified by flow visualization. As a result, tilting-link vortex was observed for the asymmetric excitation. It plays an important role for mixing and diffusion of the excited rectangular jet. The jet spreading is attributed to the tilting alignment of the vortex ring, and the jet contraction in the minor direction is due to the self-induced deformation of the rectangular vortex ring.
