Whitecapping Dissipation Research Articles

Wind-wave-current System In Coastal Ocean

Observational discoveries of coastal current structure in Ogata Coast, Japan, were summarized with respect to characteristics of wind and waves in the wave-shoaling region. The observations of flow structure under the storm condition (strong wind & high wave) showed that (1) the coastal longshore current that has a vertically uniform flow profile, was developed in the wide area of coastal zone including the surf zone, and (2) strong shear flow with undertow (offshore-going near-bottom current) was developed in the surf zone. As a generation mechanism of such flow structures, it was designated that sea surface stress was emphasized under storm condition with the energy transfer from wind to waves through whitecap dissipation of shoalkg waves. A mathematical model of whitecaps dissipation stress,z,, ,was proposed as an energy transfer interface between atmosphere and coastal ocean. Using this interface model, numerical Wind-Wave-Current System (WWC System) was established, in which the relation between wind stresses (wind field), whitecap breaker stresses (wave field) and bottom stresses (current field) were integrated. Enhancing effects of whitecap dissipation stress due to wave shoaling was also taken into consideration in the system.