A Technique for Registering Wave and Vortex Motions on a Liquid Surface

Abstract

A technique that allows simultaneous measurements of vortex and wave motions of fluids is described. To record the vortex motion, a liquid surface is decorated with light particles of PA-12 polyamide with an average diameter of 30 μm and video filming of the motion of these particles is performed. The wave motion on the water surface is recorded using an improved method that we proposed earlier for spatial recording of waves on the surface of a transparent liquid; this involves video filming of a contrast stencil lying on the bottom of an experimental pool. The distortion of the video image of the stencil through the transparent liquid layer allows the vertical velocity component to be reconstructed.