Research Article | OPEN ACCESS
The Interaction of Oscillating-Grid Turbulence with a Sediment Layer
W.H.M. Wan Mohtar and N.M. Zakaria
Department of Civil and Structural Engineering, Faculty of Engineering, National Universiti Kebangsaan, Malaysia, 43600 Bandar Baru Bangi, Selangor, Malaysia
Research Journal of Applied Sciences, Engineering and Technology 2013 4:598-608
Received: August 24, 2012 | Accepted: September 19, 2012 | Published: June 20, 2013
Abstract
This study described a preliminary experimental setup to identify how near-bed turbulence interacts with and moves sediment. The turbulence generated by a vertically oscillating grid was made to interact with a homogeneous horizontal sediment layer. Near-spherical particles were used throughout with two types of sediment at comparable sediment size d≈700 μm. The interaction characteristics were investigated by employing the PIV technique to measure the velocity field of the displaced sediment grains (within the transverse plane of the bed surface) during the interaction. Measurement of the velocity of the displaced sediment grains was restricted to the $\fracθ{θ_c}>1$ case, where $θ = \frac{τ_b}{(s-1)gd}$ is the Shields parameter, the subscript $c$ denotes critical i.e. threshold criteria, $τ_b$ is the mean bed shear stress and $s$ is relative density of sediment. During the period of interaction, the sediment grains were primarily displaced by the radial velocities and formed distinctive circular trajectories. Energetic turbulence resuspends the particles above the bed surface, forming the characteristics particle splash.
Keywords:
Sediment trajectories turbulence-particle interaction, zero-mean turbulence,
Competing interests
The authors have no competing interests.
Open Access Policy
This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
Copyright
The authors have no competing interests.
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ISSN (Online): 2040-7467
ISSN (Print): 2040-7459 |
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