Author(s): Sabagh Yazdi; Behzad Saeedifard
Linked Author(s):
Keywords: Turbulent flow; Cell centre finite volume schemes; Shallow water equation; Artificial viscosity. 1
Abstract: This paper contains results from a numerical simulation of flow in a channel with a sudden expansion that consist constant bed slop as bed forms. a depth-average model using a cell centre finite-volume method has been developed for the prediction of turbulence flow in channel with a sudden expansion in width. flow characteristics, including the mean velocity field and the Reynolds stress components are evaluated. Artificial viscosity operators are applied for damping out numerical oscillations associate with the explicit procedure of solution. Effects of bed slope of the channel is considered in the gravitational term of the momentums equations. also effects of bed resistances are considered as global forces in the sink/source terms of the two equations of motions. The choice of a turbulence model has consequences for the accuracy of the computed results, in this study Eddy viscosity computed by using zero equation (depth-averaged) model. By using depth-averaged parabolic eddy viscosity, for increasing accuracy of numerical result, coarse mesh is not used. The developed model has been tested and validated by using a two test cases of a channel with a sudden expansion in width. The velocity data were measured in a flume (Xie, 1994) for two flow discharges along 11 cross-sections from the expansion section to downstream of the recirculation zone. The predictions are compared with data from laboratory measurements. Detailed comparison of the flow field shows generally good agreement.
Year: 2007