Process of Formation of a Mushroom-type Longitudinal Vortex

Abstract

The formation of mushroom-type longitudinal vortices with streamwise axces is noticed in the boundary layer both along flat walls and along curved ones of a two-dimensional convergent nozzle. The vortex formed on the flat wall is examined experimentally. Air flow in the boundary layer is visualized by using evaporated-gasoil smoke, which is supplied to the convergent nozzle through two-types of slit-nozzles set at two of the upstream walls. Owing to staticpressure gradient perpendicular to the nozzle axis, cross-flow in the boundary layer is generated, and the cross-flow is concentrated and gradually developed into a mushroom-type vortex.