Sediment transport under oscillatory flows. (December 2020) - Vittori, Giovanna
Highlights: Direct numerical simulation of the sediment transport under sea waves Evaluation of the bed/suspended load by means of empirical formulas suitably adapted Evaluation of the time-dependent reference bottom elevation and concentration Determination of the excursion of the bottom surface during the wave cycle 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.