Author(s): Masanori Michiue; Osamu Hinokidani
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Keywords: No Keywords
Abstract: In recent years,the numerical simulation methods for a 2 dímensional bedevolution in alluvial channels have been proposed by many researchers. Forexample,Simizu et.al.[1],Ashida et.al.[2]and Yen et.al.[3]applied the 2dimensional models to calculated the bed evolutions in meandering channels,andthe results of simulation were in fairly good agreement with experimental dataof bed configuration in some extent.But in these simulation methods,the flowfield calculated on the basis of a 2 dimensional shallow water flow model isneeded,and the velocities near the bottom necessary to estimate the shearvelocities,should be calculated by the equations derived on the flat bedcondition.Therefore the applicability of these simulation methods on thecondition that the bed variation occurred similar to a natural river,is to berestricted fairly.So,in this study,the numerical simulation method of the 2dimensional bed evolution in meandering channels in which the numerical resultsof the vertical distrfbution of flow velocities at the bottom calculated by the3 dimensional numerical method are used to obtain the shear velocities,isapplfed to the previous,experiment.And results of the simulation are comparedwith the experimental data.Using the numerical results for 3 dimensional flowvelocities,the magnitude of each term on the momentum equation and the changeof flow characteristics due to the bed evolution are easily estimated.Andnumerical results of the 2 dimensional model,namely velocities near the bottomon flat bed condition and the equilibrium bed condition are compared withthe results based on the 2 dimensional shallow water model.
Year: 1991