NUMERICAL SIMULATION OF ROLL WAVES IN OVERLAND FLOW OVER MOVABLE BED

A numerical study on mobile bed hydraulics of roll waveswith sediment transport and morphological evolution is presented. Thegoverning equations of the model comprise the shallow water hydrodynamicsequations closed with the Manning formulation for the boundary resistance.The second-order Total-Variation-Diminishing version of theWeighted-Average-Flux method, along with the HLLC approximate ReimannSolver, is used to solve the governing equations, which can properly captureshock waves and deal with irregular boundaries.Brock's laboratory experiments of roll waves in a fixed-bed channel arereproduced.Numerical simulations show the development and propagationof roll waves over mobile-bed. It is shown that the morphological evolutionhas a great effect on the roll waves' dynamic characteristics.