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Motion of a vortex near a free surface[dagger]

Published online by Cambridge University Press:  26 April 2006

Peder A. Tyvand
Affiliation:
Department of Agricultural Engineering, Agricultural University of Norway, Box 65, 1432 Ås-NLH, Norway

Abstract

The early motion of a single vortex suddenly placed near a free surface is studied analytically. The general initial/boundary-value problem is solved in terms of a Taylor expansion in time. The vortex position and the surface elevation are determined to third order. We find a precise distinction between subcritical (weak) and supercritical (strong) vortices. All vortices start with retrograde horizontal motion. After a short time, subcritical vortices tend to turn and continue their motion in the prograde direction. Supercritical vortices cannot turn, but will continue their retrograde motion. They will accumulate a surface mound until surface breaking eventually occurs.

Type
Research Article
Copyright
© 1991 Cambridge University Press

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Footnotes

With an Appendix by R. P. Tong.

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