Sediment resuspension beneath periodic internal solitary waves of depression over a flat bottom

We investigate sediment resuspension beneath periodic internal solitary waves of depression over a flat bottom using two-dimensional direct numerical simulations. At Re_ISW = 300, we observe flow separation, susceptible to a convective instability, beneath the trailing shoulder of the internal solitary wave. We consider the shear-induced sediment transport at the bottom boundary along with the sediment resuspension resulting from the convective instability. The near-bed sediment transport is dominated by the maximum shear beneath the leading shoulder of the wave. This sediment propagates behind the wave, where there is a second peak in bottom shear stress in the region of flow separation. The observed convective instability triggers vortex shedding, which enhances vertical sediment transport. We discuss the conditions under which suspended sediment is transported out of the bottom boundary layer as a function of dimensionless parameters that encompass the properties of the sediment and of the flow.