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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
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| 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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