Physically Realistic Roughness Closure Scheme to Simulate Turbulent Channel Flow over Rough Beds within the Framework of LES
Publication: Journal of Hydraulic Engineering
Volume 136, Issue 10
Abstract
A physically realistic roughness closure method for the simulation of turbulent open-channel flow over natural beds within the framework of large-eddy simulation (LES) is proposed. The description of bed roughness in LES is accomplished through a roughness geometry function together with forcing terms in the momentum equations. The major benefit of this method is that the roughness is generated from one physically measurable parameter, i.e., the mean grain diameter of the bed material. A series of flows over rough beds, for which mean flow and turbulence statistics are available from experiments, is simulated. Measured and computed values are compared to validate the proposed roughness closure approach. It is found that predicted streamwise velocity profiles, turbulence intensities, and turbulent shear stress profiles match the measured values fairly well. Furthermore, the effect of roughness on the overall flow resistance is predicted in reasonable agreement with experimental values.
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Acknowledgments
Provision of data by Professor D. Webster (Georgia Institute of Technology), Professor V. Nikora (University of Aberdeen), and Dr. J. Aberle (University of Braunschweig) is gratefully acknowledged.
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Information & Authors
Information
Published In
Journal of Hydraulic Engineering
Volume 136 • Issue 10 • October 2010
Pages: 812 - 819
Copyright
© 2010 ASCE.
History
Received: Aug 1, 2009
Accepted: Mar 27, 2010
Published online: Mar 30, 2010
Published in print: Oct 2010
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