ABSTRACT
This study presents a comparison of two different model concepts for the simulation of sediment transport, namely the capacity model with the Exner equation and the non-capacity model with suspended sediment transport and erosion and deposition terms. The Exner equation is modified to account for momentum loss due to sediment particle movement. Both equations are discretized using cell-centered finite-volumes and a second order Godunov-type scheme is applied for the solution. The numerical flux is calculated by a Harten, Lax and van Leer approximate Riemann solver with the contact wave restored (HLLC). Numerical simulations of dam break flow on movable bed are carried out. In first one-dimensional test case with flow on a horizontal bed, a sensitivity study for different model parameters is carried out. The capabilities and limitations of both model concepts are demonstrated in the second benchmark experimental test case dealing with dam break flow over variable bed topography. Overall, good agreement between model results and experimental data has been obtained. It is concluded that the modified capacity model can be used for sediment transport modeling for relatively steady flow and the non-capacity can be used in the more rapid flow.
