Effect of Sediment Density on the Bed Topography in a Channel Bend Using Numerical Modeling

Abstract

In this paper, the bed topography of a channel at a 90-degree bend was studied at the T-shaped spur dike installed at the middle of the outer bank. Numerical analyses were performed with the Sediment Simulation in Intakes with Multiblock Option (SSIIM) model. Three relative curvatures (R/B =  2, 3, and 4) related to the three sediment densities (P  = 2.35, 2.5, and 2.65) were modeled in nine cases and the effects of sediment density on the bed scour patterns were studied. It was observed that the maximum amount of scour occurred near the head of the dike wing at the dike’s upstream, and the maximum amount of sedimentation occurred at the inner bank of the bend exit. By increasing the sediment density when R/B  = 4, the maximum scour and sedimentation decreased to 27.41% and 46.15%, respectively. When R/B  = 3, the maximum scour and sedimentation decreased to 25.93% and 23.91%, respectively. When R/B  = 2, the maximum scour and sedimentation decreased to 25.98% and 10%, respectively.