3-DIMENSIONAL NUMERICAL MODELING OF WATER AND SEDIMENT FLOW IN A SAND TRAP

The flow of water in a three-dimensional sand trap is calculated by a numerical model, using a finite volume method to solve the Navier-Stokes equations for three dimensions on a general non-orthogonal grid. The k-epsilon turbulence model is used to solve the Reynolds-stress term. The diffusion/convection equation for the sediment concentration is solved giving the sediment concentration in the sand trap. A physical model study carried out to verify the results shows the recirculation zone to be shorter than the numerical model result, but modifications in the turbulence model give better agreement. The sediment concentration calculations compare well with the experimental procedures. The concentration calculated by using the flow field from the original k-epsilon model gives 87.1% trap efficiency, whereas calculation with the more correct flow field gives 88.3%.