Author(s): Dimas Athanassios; Balaras Elias; Grigoriadis Dimokratis
Linked Author(s):
Keywords: Bed Dune; Open Channel; Sub-Critical Flow; Turbulence; Large-Eddy Simulation; Immersed Boundary Method
Abstract: The open-channel, sub-critical flow over fixed dune is numerically simulated and the developing turbulent coherent structures are analyzed. The study is based on a large-eddy simulation utilizing the immersed boundary method to incorporate the dune geometry. Results are presented for a typical dune shape and two Reynolds numbers Re = 17500 and Re = 93500. A primary flow circulation region develops downstream of the dune crest at both Reynolds numbers, while a secondary circulation region develops in the toe of the dune crest only for the low Reynolds number. Downstream of the primary circulation region, hairpin-like vortices develop, which, as they are convected along the upslope part of the next dune, they get stretched and weaken.
Year: 2007