Computation of Flow, Turbulence and Bed Evolution with Sand Waves

A vertical two-dimensional morphodynamic model with non-hydrostatic, free surface flow is reported herein. This numerical model can simulate flow and turbulence characteristics over sand waves. Likewise, model can reproduce the sand wave formation and migration process as well as free surface oscillation simultaneously in a moving boundary domain with the implication of a generalized coordinate system. A nonlinear k-ε model is employed as a turbulence closure. CIP numerical technique is used to resolve advection term of momentum equations. An Eulerian stochastic formulation of sediment exchange process in terms of pick up and deposition function is incorporated to simulate non-equilibrium sediment transport that explicitly considers the flow variability during morphodynamic computation. The numerical model is validated with experimental data on flow and turbulence over fixed dunes as well as laboratory measurement and visualization of dune geometry and migration.