The formation and development of fluid mud layer under the both factors of current and wave that often happens in estuaries and coastal areas are studied in detail through numerical simulation on the basis of the 2D shallow water equations for tidal flow, the advection-diffusion equation for sediment transport and the equations for fluid mud transport. | Vietnam Journal of Mechanics, NCNST of Vietnam T. XX, 1998, No 3 (5- 15) NUMERICAL SIMULATION OF FLUID MUD LAYER UNDER CURRENT AND WAVES IN ESTUARIES AND COASTAL AREAS DANG HUU , Institute of Mechanics, 224 Doi Can, Hanoi, Vietnam Tel: 0084-4-8326138 Fax: 0084-4-8333039 Email: dhchung@ ABSTRACT. The formation and development of fluid mud layer under the both factors of current and wave that often happens in estuaries and coastal areas are studied in detail through numerical simulation on the basis of the 2D shallow water equations for tidal flow, the advection-diffusion equation for sediment transport and the equations for fluid mud transport. At the same time the model for wave propagation is also included. Numerical solution of a special case for a part of the Severn estuary is obtained using the finite difference method as an illustration of the applicability of the model in practice. 1. Introduction Cohesive sediment transport plays an important role in a wide rage of design, maintenance and management problems in estuaries and coastal regions. Accumulation of sediment in navigation channels and berths often requires very expensive dredging operations. Once a new development appears, it can cause significant changes to the sediment transport patterns, so a good understanding of the likely changes is necessary before any engineering project can proceed. In addition, many pollutants are preferentially adsorbed on to the fine cohesive fraction of the sediment and therefore for environmental reasons it is important to be able to predict the movement of the sediment. In estuaries and coastal regions where there is a high concentration of sediment in suspension, a fluid mud layer is often formed during slack water periods by the process of hindered settling. This amount of sediment comes from the sea or from rivers due to the process of flowing through many areas in a country or around the sides of mountains. Once the near bed .
