Author(s): M. M. Ali; P. Steffler
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Keywords: Shallow water flow; Shock capturing schemes; Friction term dominated; Finite Volume Method; Fourier analysis; Numerical Friction number
Abstract: Numerical modeling of one-dimensional (1D) and two-dimensional (2D) open channel flows with irregular bed topography is challenging, especially when frictional slope and bed slope dominate. Non-physical oscillations in the flow rate and/or depth solutions can occur in most schemes when there are steep slopes, shallow flows, or coarse discretization. In this paper we studied three different first order finite volume shock capturing numerical schemes with a simple 1D sub-critical non-uniform steady state test case with two sudden slope changes. The result showed that downwind approximations for both the pressure force and the bed slope produce oscillation free solutions, whereas the basic Godunov scheme and the balanced of source terms and flux gradients type Godunov scheme produce oscillations in the flow rate and/or in the depth variable solutions. The oscillations increase with the increasing of the numerical Friction number.
Year: 2011