Modelling sand resuspension by waves over a rippled bed

With a two-dimensional K-E model and equations to describe sediment entrainment, diffusion, convection and settling, wave-induced flow velocities and sediment concentration fields over rippled beds have been calculated. Results from the simulations are compared with time-averaged vertical suspended sediment concentration profiles, C-profiles, measured in a large wave flume using the autonomous multi-sensor instrument STABLE. The simulations make it possible to examine in detail the mechanisms of sediment entrainment, vortex formation and advection. The resulting animations of model output allow a quasi-3-D visualization of sediment resuspension processes and aid quantification of the resulting vertical suspended sediment concentration field due to regular waves, asymmetric waves and wave groups. The work contributes therefore, to knowledge about wave-sediment interactions and to understanding of sediment transport mechanics. (C) 2000 Academic Press.