Author(s): A. Paquier; S. Massart; M. Krzyk; M. Cetina
Linked Author(s): Matjaz Cetina, André Paquier
Keywords: 2-D mathematical models; Suspended sediment transport; PCFLOW2D; Rubar 20; Ptuj Lake
Abstract: A comparison of 2-D models for flow and sediment transport simulations is presented in the paper. PCFLOW2D and TCONC of the University of Ljubljana model steady flow on a rectangular grid while Rubar 20 of CEMAGREF can treat unsteady flow on an irregular curvilinear grid. Shallow water equations and advection diffusion equation for suspended sediment transport are solved numerically by the control volume method. The main differences between both models are that PCFLOW2D uses a depth-averaged version of the k-εturbulent model while Rubar 20 keeps turbulent viscosity and diffusion coefficients constant. Formulations of the source term describing the exchange of sediments are also slightly different. Both models were compared on the real case of Ptuj Lake which is a reservoir on the River Drava near the town Ptuj in the North East of Slovenia. After the models were calibrated with velocity and sediment deposition measurements from 1981, 1991 and 1993, three different calculations were performed: PCFLOW2D on a rectangular grid of 25 by 50 m, Rubar 20 on the same grid and Rubar 20 on a grid fitted to the lake banks. Comparison of both models showed a similarity in the water levels and velocity fields although locally some differences appear due to different interpolations of the bottom topography. For deposits the similarity is not so obvious because of three main causes that were identified: deviation in hydrodynamic results, differences in numerical solvers and different computations of the source term. The calibration of the parameters of this source term is the most difficult and time consuming task.