Computational Fluid Dynamics in Fluvial Sedimentation Engineering
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The present dissertation describes the improvement of a numerical model when predicting sedimentation and erosion processes in fluvial geomorphology. Various algorithms and parameters were implemented in a computational fluid dynamic model for simulation of three-dimensional water flow and coupled sediment transport to gain an insight into the capabilities of the numerical model. Within the scope of the test cases the model simulated suspended load concentrations at a water intake, transient bed deformation in a 90º channel bend, grain sorting processes as well as an unsteady flow regime in a 180º channel bend, transient bed deformation in a sine-shaped meandering channel with occurring bed forms and the free-forming meander evolution of an initially straight channel. All results matched well with the measurements. The results also showed that using computational fluid dynamics for modeling water flow and sediment transport is one step closer of having a universal predictor for processes in fluvial geomorphology. However, there are limitations and some uncertainties in computing the water surface location and alluvial roughness as well as in turbulence modeling. These should be clarified in future investigations.
Består avRüther, N; Singh, J.M; Olsen, N.R.B; Atkinson, E. 3D computation of sediment transport at water intakes. ICE, Procceedings of the Institution of Civil Engineers. 158(WMI): 1-8, 2005.
Rüther, N; Olsen, N.R.B. Three dimensional modeling of sediment transport in a narrow 90º channel bend. Journal of Hydraulic Engineering. 131(10): 917-920, 2005.
Rüther, N; Olsen, N.R.B. Modelling free-forming meander evolution in a laboratory channel using three dimensional computational ﬂuid dynamics. Geomorphology. 89(3-4): 308-319, 2007.