Effect of Unsaturated Coastal Seepage on Sediment Transport in Swash Zone

Abstract

A numerical simulation is performed to evaluate the influence of wave-driven coastal seepage on sediment transport in swash zone. The tractive velocity of swash motion and infiltration-exfiltration rate are estimated using a Navier-Stokes model coupled with a porous flow model incorporated the unsaturated region. The tractive force under the influence of seepage is quantified through a permeable Shields parameter, which is concerned with both the effective weight of sediment and swash boundary layer thickness. The comparison between model results and previous experimental data shows that the direction of sediment transport changed from onshore to offshore can be evaluated by the infiltration-exfiltration process.