Ambient Free Surface Wave Modification by a Submerged Vortex Pair
Abstract
This research examines how free surface gravity waves travelling over a fluid are modified by the presence of a submerged pair of vortex singularities. The understanding of vortex flows near a free surface has become goal in the hydrodynamics community over the last decade due to its possible importance in determining the influence of vortical ship wakes on radar images of the ocean surface, a theory for vortical influence on ambient free surface waves has not been addressed. The inclusion of ambient surface wave modification by submerged vortices are taken by concentrating on three questions. First, what is the important physical mechanism of influence of the vortex on free surface ambient waves? Second, in formulating a typical vortex model of the flow involving a rising pair, what parameters are significant in determining the form of the ambient wave modification? And finally, how can this information be useful in the practical problem of radar imaging of ship wakes? Careful analytic analysis of the free surface boundary conditions will show that the induced surface current generated by the vortices provides the physical mechanism of ambient wave modification. A numerical model is described which is utilized to determine the relative importance of parameters derived in the analytic analysis on this physical mechanism. In addition, spectral analysis is performed to highlight the use of simulation results in evaluation of conditions applicable to the problem of radar remote sensing of ship wakes. (jg)
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 1990
- Accession Number
- ADA219666
Entities
People
- Scott Fish