Open AccessCOHERENT EDDIES INDUCED BY BREAKERS ON A SLOPING FIELD
Author(s) -
Nobuhiro Matsunaga,
Kosei Takehara,
Yoichi Awaya
Publication year - 1988
Publication title -
proceedings of conference on coastal engineering/proceedings of ... conference on coastal engineering
Language(s) - English
Resource type - Journals
eISSN - 2156-1028
pISSN - 0589-087X
DOI - 10.9753/icce.v21.15
Subject(s) - eddy , mechanics , geology , instability , submarine pipeline , vortex , boundary layer , geotechnical engineering , physics , turbulence
The separation of boundary layer occurs periodically near a breaking point when incident waves climbing up a sloping bed are about to break. Not the breaker but the separation forms an unsteady coherent eddy, which suspends a large amount of bed material. A row of steady vortices has been found along the water surface of an offshore zone. Its formation is due to the shear instability between shoreward steady flow induced near the bed and offshore steady flow near the water surface. Moving in the offshore direction, the steady vortices repeat amalgamation each other and increase their intervals at the order of mean water depth. They decay after reaching to the region where the shear rate is not enough between the two steady flows. This shear instability may be excited by the periodic separation of boundary 1aye r.