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A numerical simulation of morphological processes for a navigation channel

The finite difference method was applied to simulate the morphological processes for a. navigation channeL Mathematical equations were based on the SUTRENCH and PROFILE models proposed by L. C. van Rijn. The difficulties of treatment for bed boundary conditions were overcame flexibly by using the interpolation functions with high accuracy. The results obtained showed that the simulation is very suitable and able to be applied to practice problems. | T~p chi Ccr h9c Journal of Mechanics, NCNST of Vietnam T. XVII, 1995, No 1 (22- 27) A NUMERICAL SIMULATION OF MORPHOLOGICAL PROCESSES FOR A NAVIGATION CHANNEL NGUYEN VAN DIEP and DANG HUU CHUNG lnst£tute of Mechanics, NCNST of Vietnam SUMMARY. The finite difference method was applied to simulate the morphological processes for a. navigation channeL Mathematical equations were based on the SUTRENCH and PROFILE models proposed by L. C. van Rijn. The difficulties of treatment for bed boundary conditions were overcame flexibly by using the interpolation functions with high accuracy. The results obtained showed that the simulation is very suitable and able to be applied to practice problems. 1. INTRODUCTION The morphological process is a popular phenomenon happening in rivers, estuaries and coastal regi_ons, especially in environments with a predominant suspended load. According to Ida Broker Hedegaird et al. [2] that is the interaction between hydrodynamic conditions and bed level evolution. This problem has been interesting several scientists in the world. Up to now there are many mathematical models for this [7L but the model in which the turbulence of flow is taken into account, may be more suitable. Knowledge on this process is really necessary because several studies in practice are required, such as harbour project, in which the rate of sedimentation in the navigation channel may be one of the most important economic aspects, and can be the parameter that fin·ally decides the optimal location of the harbour. 2. MATHEMATICAL MODEL Using the assumptions of the quasi-steady flow, the longitudinal diffusion term being neglected in comparision with the vertical diffusion term and the one of unsteady concentration bemg relatively small in relation to the others, the system of equations describing sediment How perpendicular to channel axis are as follows [5-6) u = A 1 u,In(zjz0 ) + u, (1- A 1 hln(h/z 0 )) (2ry'- ry 2 ') 1 a aw --(bu)+-=0 b ax az 1 a a a .