Turbulence in mobile-bed streams

Dey, Subhasish ; Das, Ratul ; Gaudio, Roberto ; Bose, Sujit K. (2012) Turbulence in mobile-bed streams Acta Geophysica, 60 (6). pp. 1547-1588. ISSN 1895-6572

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Official URL: http://link.springer.com/article/10.2478%2Fs11600-...

Related URL: http://dx.doi.org/10.2478/s11600-012-0055-3


This study is devoted to quantify the near-bed turbulence parameters in mobile-bed flows with bed-load transport. A reduction in near-bed velocity fluctuations due to the decrease of flow velocity relative to particle velocity of the transporting particles results in an excessive near-bed damping in Reynolds shear stress (RSS) distributions. The bed particles are associated with the momentum provided from the flow to maintain their motion overcoming the bed resistance. It leads to a reduction in RSS magnitude over the entire flow depth. In the logarithmic law, the von Kármán coefficient decreases in presence of bed-load transport. The turbulent kinetic energy budget reveals that for the bed-load transport, the pressure energy diffusion rate near the bed changes sharply to a negative magnitude, implying a gain in turbulence production. According to the quadrant analysis, sweep events in mobile-bed flows are the principal mechanism of bed-load transport. The universal probability density functions for turbulence parameters given by Bose and Dey have been successfully applied in mobile-bed flows.

Item Type:Article
Source:Copyright of this article belongs to Springer-Verlag.
Keywords:Flow Characteristics; Hydraulics; Open-channel Flow; Sediment Transport; Stream Beds; Turbulent Flow
ID Code:89234
Deposited On:24 Apr 2012 12:19
Last Modified:19 May 2016 03:49

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