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Effects of a fully submerged boulder within a boulder array on the mean and turbulent flow fields: Implications to bedload transport
- Source :
- Acta Geophysica. 60:1502-1546
- Publication Year :
- 2012
- Publisher :
- Springer Science and Business Media LLC, 2012.
-
Abstract
- The objective of this coupled experimental and numerical study is to provide insight into the mean and turbulent flow fields within an array of fully submerged, isolated, immobile boulders. Our study showed that the velocity defect law performed well for describing the mean flow around the boulder within the array. A prerequisite, however, was to accurately estimate the spatial variability of u* around the boulder, which was achieved via the boundary characteristics method. The u* exhibited considerable spatial variability within the array and form roughness was shown to be up to 2 times larger than the skin roughness in the boulder near-wake region. Because the boulders bear a significant amount of the flow shear, the available bed shear stress for entrainment of the mobile sediment, τ ols , near the boulders was roughly 50% lower than the ambient τ ols . The τ ols variability induced by the boulders could lead to a threefold overestimation of the sediment transport rate.
Details
- ISSN :
- 18957455 and 18956572
- Volume :
- 60
- Database :
- OpenAIRE
- Journal :
- Acta Geophysica
- Accession number :
- edsair.doi...........48a2fcb1d8cf786553383345ecc40a4f