Accession Number : ADA333400

Title :   Nearshore Currents over a Barred Beach

Descriptive Note : Doctoral thesis

Corporate Author : NAVAL POSTGRADUATE SCHOOL MONTEREY CA

Personal Author(s) : Faria, Antonio Fernando Garcez

PDF Url : ADA333400

Report Date : JUN 1997

Pagination or Media Count : 178

Abstract : The objective of this dissertation is to develop numerical models and compare their predictions with data acquired during the DUCK94 experiment in order to improve our physical understanding of the hydrodynamic processes governing the vertical and cross shore distributions of both longshore and cross shore currents over a barred beach. The vertical structure of the mean longshore current is found to be well described by a logarithmic profile and a relationship between bed shear stress and bottom roughness, including the influence of ripples and mega-ripples, was also found. The vertical structure of the mean cross shore current (undertow) is modeled using an eddy viscosity closure scheme to solve for the turbulent shear stress and includes contributions from breaking wave rollers. These models of the vertical profiles of longshore and cross shore mean currents are combined to formulate a quasi three dimensional model to describe the cross shore distribution of the longshore current. This model includes turbulent mixing due to the cross shore advection of mean momentum of the longshore current by the mean cross shore current and contributions from wave rollers.

Descriptors :   *OCEAN CURRENTS, *OCEAN MODELS, *HYDRODYNAMICS, *BEACHES, OCEAN WAVES, SURFACE ROUGHNESS, THESES, TURBULENT FLOW, EDDIES(FLUID MECHANICS), RIPPLES, OCEAN BOTTOM TOPOGRAPHY, SHEAR FLOW, CROSS FLOW, THREE DIMENSIONAL FLOW.

Subject Categories : Physical and Dynamic Oceanography
      Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE