Sensitivity of Suspension Pattern of Numerically Simulated Sediments to Oscillating Periods of Channel Flows over a Rippled Bed SCIE SCOPUS KCI

Cited 1 time in WEB OF SCIENCE Cited 1 time in Scopus
Title
Sensitivity of Suspension Pattern of Numerically Simulated Sediments to Oscillating Periods of Channel Flows over a Rippled Bed
Author(s)
Chang, Yeon S.; Hwang, Jin H.; Park, Young-Gyu
KIOST Author(s)
Chang, Yeon S.(장연식)Park, Young Gyu(박영규)
Publication Year
2017-07
Abstract
In this study, we investigated the sediment suspension process over a ripple, using large eddy simulation and a Lagrangian particle tracking model to numerically calculate the individual motion of sediment grains in turbulent boundary layer flows. We examined the relationship of the sediment convection process with the formation of lee eddies at the back of the ripple. We tested three flow conditions by changing the oscillating period while keeping other conditions. In all three cases lee eddies developed, but they formed at different flow phases and differed in their duration. These lee eddies significantly influenced the turbulent kinetic energy distribution and sediment suspension pattern as they showed phase differences between the cases, according to their lee eddy formation. We compared two types of sediment suspension rates by counting the number of suspended sediment grains. Both these rates showed that maximum sediment pick-up occurred earlier in the oscillating flow phase as the period increased, but the magnitude of the pick-up rate decreased with increasing period. The results of our study indicate that the suspension pattern may vary significantly with the period. Therefore, formulas for sediment pick-up rates, which usually give maximum rates at the time of flow reversal over ripples, may require an additional controlling factor-the oscillation period. The sediment suspension pattern, however, shows some discrepancies from that observed by van der Werf et al. (2007) as the sediments were not suspended at the time of flow reversal. This is likely due to the low steepness of the ripple and the employment of an unrealistically small sediment size in our study experiment.
ISSN
1226-7988
URI
https://sciwatch.kiost.ac.kr/handle/2020.kiost/1202
DOI
10.1007/s12205-016-0516-3
Bibliographic Citation
KSCE JOURNAL OF CIVIL ENGINEERING, v.21, no.5, pp.1503 - 1515, 2017
Publisher
KOREAN SOCIETY OF CIVIL ENGINEERS-KSCE
Subject
LARGE-EDDY SIMULATION; TURBULENT-BOUNDARY-LAYERS; STEEP RIPPLES; SAND RIPPLES; SEA WAVES; TRANSPORT; PARTICLES; STEADY; MODELS; LES
Keywords
coastal sediment transport; sediment suspension; ripple; periodic flows; Lagrangian particle motion
Type
Article
Language
English
Document Type
Article
Publisher
KOREAN SOCIETY OF CIVIL ENGINEERS-KSCE
Related Researcher
Research Interests

ocean circulation,ocean mixing,marine debris,해양순환,해양혼합,해양부유물

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