Free Surface Scars and Striations
Abstract
A numerical and experimental investigation of the inter action of a pair of vortices with a free surface has been undertaken. The analysis is based on the vortex-sheet representation of the free surface and the use of the appropriate boundary conditions. The experiments were performed in a large basin and the vortices were generated through the use of a special nozzle. The rise of the resulting Kelvin oval, the trajectories of the vortices, and the instantaneous shape of the free surface were recorded on a video tape and then carefully analyzed through the use of a Motion Analysis system. The results have shown that the rise of the vortices not only gives rise to two scars, with a pronounced hump in the middle, but also, and more importantly, to a three- dimensional instability heretofore unknown. The measured and calculated vortex trajectories and the free-surface shapes at the corresponding times and Froude numbers are found to be in reasonable agreement. The new instability will form the basis of future investigations.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1989
- Accession Number
- ADA212429
Entities
People
- Douglas H. Rau
Organizations
- Naval Postgraduate School