Sediment transport under oscillatory flows

TL;DR

This study uses direct numerical simulations to analyze sediment transport under oscillatory flows, explicitly computing flow-particle interactions to evaluate sediment movement relevant to offshore sea wave conditions.

Contribution

It introduces a detailed numerical approach to quantify sediment transport during oscillatory flows, testing empirical formulas against simulated data.

Findings

Validated empirical sediment transport formulas against simulations

Quantified sediment movement for different flow and particle parameters

Provided insights into sediment dynamics under wave-induced oscillatory flows

Abstract

The results of Direct Numerical Simulations of the oscillatory flow over a cohesionless bed of spherical particles, mimicking sediment grains, are described. The flow around the sediment particles is explicitly computed by using the immersed boundary method, which allows the force and torque acting on the particles to be evaluated along with their dynamics. Different values of the Reynolds number and different values of the ratio between the grain size and the thickness of the boundary layer are considered such that the results are useful to quantify the sand transport generated by sea waves in the region offshore of the breaker line. Therefore, the results are used to test the capability of empirical sediment transport formulae to predict the sediment transport rate during the oscillatory cycle.