Experimental studies on the interaction of vortex pairs with wind waves.

摘要

Experimental studies were conducted to investigate the sea-surface fine structures modified by vortex pairs. A submerged sphere in a current field generated the vortex pairs. Laboratory experiments were carried out under controlled conditions of wind, wave, and current in our Wind-Wave-Current Research Facility.; The study was first conducted by investigating the video images of these vortices appearing on the water surface. The occurrence of the vortices' appearance was readily seen in these images. Video observations showed that the vortex shedding frequency on the water surface not only changed with the Reynolds number but also changed with the sphere depth. These images also suggest the depth effects on the propagation speed. The study was then conducted by analyzing the surface slopes that were mapped with our scanning laser slope gauge (SLSG). The SLSG had a scanning speed fast enough to catch the evolution of each component of vortex pairs. The appearance of vortices can be identified by the analyzing of upwind-downwind and crosswind slopes in time domain.