Author(s): Souliotis D. ; Prinos P.
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Keywords: No Keywords
Abstract: In the present paper three dimensional computations, based on the Reynolds Averaged Navier Stokes (RANS) equations and two turbulence models of the k-εtype, based on vegetation dynamics and on a porous media approach respectively, have been performed for calculating the mean flow and turbulence characteristics in a partially vegetated open channel for constant plant density and various vegetation widths. In addition the momentum exchange mechanism in the interface region is studied. The vegetation is simulated with rigid cylinders of diameter 0. 0065m which cover the full water depth. In this study three cases are considered with water depth 0. 068m, flume width 1. 2m, porosity 0. 98, while the vegetation to flume width ratio takes values between 0. 33 and 0. 66. The computed results, using the CFD Fluent code are compared with semi-empirical relations, derived from the vortexbased model of White and Nepf (2008), and experimental data of the same researchers. The comparison indicates the satisfactory performance of the turbulence models used for the cases studied. The effect of vegetation to flume width ratio on the flow characteristics within the free channel is also pronounced.
Year: 2010