Transport and Resuspension of Fine Particles in a Tidal Boundary Layer near a Small Peninsula

Abstract

The authors present a theory on the transport and resuspension of fine particles in a tidal boundary layer when the ambient tidal flow is nonuniform due to a peninsula along the coastline. As a first step toward better physical understanding the authors adopt the model of constant eddy viscosity and a horizontal seabed. Attention is focused on a peninsula whose horizontal dimension is much smaller than the tidal wave length but larger than the tidal excursion length. General expressions of shear-induced dispersivities and convection velocity are derived in terms of the ambient flow field. Nonuniformity in the horizontal flow is found to have profound effects on the spatial variation of the dispersion tensor as well as the horizontal convection velocity. Two numerical examples are given for a semicircular peninsula: one for a particle cloud released near the peninsula over a nonerodible seabed, and one for the resuspension over an erodible belt around the peninsula.