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iDEA: Drexel E-repository and Archives > Drexel Academic Community > College of Engineering > Department of Civil, Architectural,and Environmental Engineering > Proceedings of the 7th International Conference on HydroScience and Engineering (ICHE 2006) [ISBN: 0977447405] > Turbulence measurements in shallow flows in gravel-bed rivers

Please use this identifier to cite or link to this item: http://hdl.handle.net/1860/1359

Title: Turbulence measurements in shallow flows in gravel-bed rivers
Authors: Franca, M.J.
Lemmin, U.
Keywords: River morphodynamics;Bed roughness;Fluvial hydraulics
Issue Date: 13-Sep-2006
Publisher: Michael Piasecki and College of Engineering, Drexel University
Citation: Proceedings of the Seventh International Conference on Hydroscience and Engineering, Philadelphia, PA, September 2006. http://hdl.handle.net/1860/732
Abstract: Input from actual field measurements is required by river modelers in order to improve turbulence equation closures in hydrodynamic models. This paper is based on 3D ADVP river measurements taken in a gravel-bed river under shallow and stationary flow conditions. The blockage ratio is h/D503.0. It was found that the flow depth can be divided into three inviscid layers: roughness layer (z<0.20h); intermediate layer (0.20h<z<0.80h); surface layer (z>0.80h). The turbulence distribution was measured and analyzed including all the components of the Reynolds stress tensor (RST). The streamwise turbulent intensity dominates the TKE, representing between 50 to 80% of the TKE. Spanwise and vertical contributions throughout the flow depth are analyzed as well. A comparison of the results with empirical formulas given by previous authors to describe normal RST components shows their limitations in the roughness layer of the flow. In the roughness layer, RST shear stresses other than the longitudinal acquire more importance and occasionally prevail. In the intermediate layer, the flow is 2D and the velocity distribution is mainly logarithmic. Here, the longitudinal Reynolds shear stress distribution is linear and self-similar; the influence of bed roughness and surface irregularities is smoothed out and a combined shear effect is exerted.
Description: Paper presented at The Seventh International Conference on HydroScience and Engineering (ICHE)hosted by the College of Engineering at Drexel Univeristy on September 10-13, 2006 in Philadelphia, Pennsylvania. The conference theme was IT in the Field of HydroSciences. It included several mini-symposia that emphasized IT topics in HydroSciences and the yearly meeting of the metadata group of the International Oceanographic Data and Information Exchange organization.
URI: http://hdl.handle.net/1860/1359
ISBN: 0977447405
Appears in Collections:Proceedings of the 7th International Conference on HydroScience and Engineering (ICHE 2006) [ISBN: 0977447405]

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