Interaction of a vortex ring and the interface of immiscible liquids

Abstract

The dynamics of a vortex ring heading to an immiscible interface on normal direction are studied experimentally. A vortex ring is generated by the piston-cylinder type vortex-ring generator with various piston velocity, stroke length and tube diameter. High-speed video imaging and PIV (Particle Image Velocimetry) are used to obtain evolution of the interface of immiscible liquids and a structure of a vortex ring. Depending on stroke length-to-diameter ratios (stroke ratio), Froude number and Bond number, a variety of immiscible interface deformation modes is observed: no deformation, no rebounding jet, rebounding jet, concave rebounding jet, and symmetry breakup mode. The shape and size of the deformed interface in deforming phase have a similarity at equivalent deformation depth for all modes excluding no deformation mode. In the ipping over process of concave rebounding jet and symmetry breakup mode, the dominant secondary vortex ring is observed. In most cases, parameters for deformation, maximum depth, height and width, depend on Froude number and Bond number and stroke ratio. However, maximum deformation depth depends on Froude number and stroke ratio. Experimental results as well as scaling model conrm the maximum deformation depth tendency to Froude number and stroke ratio.