Longitudinal Vortex Structure in the Flow Field Produced by a Vortex Ring Impinging on a Flat Plate

Abstract

The flow field produced by a vortex ring at Re=2600 impinging on a flat plate was examined in detail using a smoke visualization method. The longitudinal vortex structure with a finger-like configuration was found which plays a crucial role in forming azimuthal coherent structures with a cross section resembling that of an orange; the structures promote the flow field into turbulent state. The generating and developing process of the longitudinal vortex was discussed, and the topological aspects were inferred by integrating information obtained through various local visualizations.