2D Modelling of turbulant transport of cohesive sediments in shallow reservoirs

[摘要] Modelling of the transport of fine cohesive sediments, as found in most South Africanreservoirs, has not been well developed. This is because the transport processes that areinvolved are complex and the theories not as implicit as the traditional equilibriumtransport theories for coarse non-cohesive sediment. Advection and dispersion are found tobe the processes that best describe the transport of fine sediments in turbulent flowconditions.A two-dimensional modelling tool, MIKE 21C, which simulates reservoir hydrodynamicsand cohesive sediment transport processes with an advection-dispersion model, wasevaluated in this thesis. The creation of such a numerical model involves the setting up ofa suitable curvilinear grid and requires data on the bathymetry, recorded inflows as well aswater levels. It also requires sediment characteristic parameters and transport parameters.These parameters have to be specified by the user based on previous studies and fieldmeasurement data.MIKE 21C was applied to laboratory flume tests and reservoir case studies in the field inorder to determine the effects that these parameters have on the sediment transport in aseries of sensitivity studies. Ranges were determined within which these parameter valuesshould fall. A procedure was also developed through which reservoir sedimentationmodels can be calibrated.

[发布机构] Stellenbosch University