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You are here : eLibrary : IAHR World Congress Proceedings : 32nd Congress - Venice (2007) : THEME D: Maritime and Coastal Research and Engineering : Two-dimensional large eddy simulations for shallow-flows: a case of a backward facing step flow
Two-dimensional large eddy simulations for shallow-flows: a case of a backward facing step flow
Author : Awad Esam, Toorman Erik, Lacor Chris
Shallow flows are confined turbulent shear flows and occurring in estuaries and coastal zones (Jirka and Uijttewaal 2004). The confinement of these flows results in the possibility of dividing the energy spectra into two distinguished types of turbulence; the three-dimensional turbulence generated by the wall bounded shear flow, and the quasi-2D turbulence structures (Jirka and Uijttewaal 2004; Nadaoka and Yagi 1998). Deep insights in the dynamics of the quasi-2D turbulence can be gained from simulation techniques that calculate directly the turbulent motions (Tukker 1997; Uittenbogaard 2003). There are several levels of details at which turbulent flow can be simulated. These details depend on the difference between the resolved and the modelled part of the total turbulent kinetic energy. The two-dimensional large eddy simulation (2D-LES) can be classified as intermediate level of details (van Prooijen 2004). It relies on the same principles as the 3D large eddy simulation but the filter width is much larger. The only resolved motion in case of the 2D-LES is the horizontal large scale eddies. A two-dimensional large eddy simulation (2D-LES) code with an implicit filtering operator has been developed and implemented for a backward facing step (BFS) flow using a standard Smagorinsky subgrid scale (SGS) model. In this article, a comparison has been carried out between the output of this 2D-LES code, the horizontal large eddy simulation (HLES) module of Delft3D (Uittenbogaard 2003; Uittenbogaard and van Vossen 2004) and the experimental data of (Stelling and Wang 1984). In general, there is a good qualitative agreement between these two modules.
File Size : 534,313 bytes
File Type : Adobe Acrobat Document
Chapter : IAHR World Congress Proceedings
Category : 32nd Congress - Venice (2007)
Article : THEME D: Maritime and Coastal Research and Engineering
Date Published : 01/07/2007
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