Vertical structure of mean cross-shore currents across a barred surf zone

Journal of Geophysical Research C: Oceans
By:  and 

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Abstract

Mean cross-shore currents observed across a barred surf zone are compared to model predictions. The model is based on a simplified momentum balance with a turbulent boundary layer at the bed. Turbulent exchange is parameterized by an eddy viscosity formulation, with the eddy viscosity Aυ independent of time and the vertical coordinate. Mean currents result from gradients due to wave breaking and shoaling, and the presence of a mean setup of the free surface. Descriptions of the wave field are provided by the wave transformation model of Thornton and Guza [1983]. The wave transformation model adequately reproduces the observed wave heights across the surf zone. The mean current model successfully reproduces the observed cross-shore flows. Both observations and predictions show predominantly offshore flow with onshore flow restricted to a relatively thin surface layer. Successful application of the mean flow model requires an eddy viscosity which varies horizontally across the surf zone. Attempts are made to parameterize this variation with some success. The data does not discriminate between alternative parameterizations proposed. The overall variability in eddy viscosity suggested by the model fitting should be resolvable by field measurements of the turbulent stresses. Consistent shortcomings of the parameterizations, and the overall modeling effort, suggest avenues for further development and data collection.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Vertical structure of mean cross-shore currents across a barred surf zone
Series title Journal of Geophysical Research C: Oceans
DOI 10.1029/94JC00427
Volume 99
Issue 7
Year Published 1994
Language English
Publisher American Geophysical Union
Contributing office(s) Coastal and Marine Geology Program
Description 20 p.
First page 14223
Last page 14242
Online Only (Y/N) N
Additional Online Files (Y/N) N