Time-averaged Turbulent Flow Characteristics over a Highly Spatially Heterogeneous Gravel-Bed

Article Type

Research Article

Publication Title

Acta Geophysica

Abstract

The present study focuses on the time-averaged turbulence characteristics over a highly spatially-heterogeneous gravel-bed. The time-averaged streamwise velocity, Reynolds shear and normal stresses, turbulent kinetic energy, higher-order moments of velocity fluctuations, length scales, and the turbulent bursting were measured over a gravel-bed with an array of larger gravels. It was observed that the turbulence characteristics do not vary significantly above the crest level of the array as compared to those below the array. The nondimensional streamwise velocity decreases considerably with a decrease in depth below the array. Below the array, the Reynolds shear stress (RSS) deviates from the gravity-law of RSS distributions. Turbulence intensities reduce below the crest level of the gravel-bed. The third-order moments of velocity fluctuations increase below the crest level of the gravel-bed and give a clear indication of sweeps as the predominating event which were further verified with the quadrant analysis plots. The turbulent length scales values change significantly below the crest level of the gravel-bed.

First Page

1797

Last Page

1824

DOI

10.1515/acgeo-2016-0070

Publication Date

10-1-2016

Comments

Open Access; Hybrid Gold Open Access

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