Large-Eddy Simulation of Turbulent Flow over a Fixed Two-Dimensional Dune
Publication: Journal of Hydraulic Engineering
Volume 132, Issue 7
Abstract
Turbulent open-channel flow over a two-dimensional dune is studied using an established large-eddy simulation code. The free surface is approximated as a shear free boundary. Turbulence statistics and instantaneous flow structures are examined. Numerical results from two computational grids agree with each other, and are also in good agreement with recently obtained experimental data. The mean velocity profiles show significant changes along the dune and there is no region that conforms to the standard law-of-the-wall. Profiles of the Reynolds stresses show distinct peaks marking the shear layer that originates from flow separation at the dune crest. Secondary peaks found further from the dune are ascribed to the shear layer over the upstream dune. Details of the separated flow and development of the flow after reattachment are well predicted. Quadrant analysis of the Reynolds shear stress shows that turbulent ejections dominate the near-wall motions. Complex water surface flow structures are visualized.
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Acknowledgments
This work was partially sponsored by ONR ONRN00014-01-0262. The writers thank R. L. Street and Y. Zang for providing the LES code, and also thank R. Balachandar for the experimental data.
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Information & Authors
Information
Published In
Journal of Hydraulic Engineering
Volume 132 • Issue 7 • July 2006
Pages: 643 - 651
Copyright
© 2006 ASCE.
History
Received: Jan 7, 2004
Accepted: Jul 29, 2005
Published online: Jul 1, 2006
Published in print: Jul 2006
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