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Flow Structures in the Vicinity of a Submerged Boulder within a Boulder Array.

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Title: Flow Structures in the Vicinity of a Submerged Boulder within a Boulder Array.
Authors: Baki, Abul Basar M.1 baki@ualberta.ca, Wenming Zhang2 wenming@ualberta.ca, Zhu, David Z.3 david.zhu@ualberta.ca, Rajaratnam, Nallamuthu4 nrajaratnam@ualberta.ca
Source: Journal of Hydraulic Engineering. May2017, Vol. 143 Issue 5, p1-13. 13p.
Subjects: Boulders, Turbulent flow, Fishways, Fish habitat improvement, Statistical correlation
Abstract: Boulders are widely used in fish habitat enhancement structures or fish passes. This study provides a detailed measurement of mean and turbulent flow around a boulder in a boulder array under a wake-interference flow condition. It was found that the vertical profiles of normalized streamwise mean velocity and streamwise turbulent intensity were approximately similar around the boulder, but both had different shapes in the upstream, downstream, and left and right sides of the boulder. The profiles of streamwise mean velocity deviated substantially from the classic logarithmic law but agreed with the Coles' wake law fairly well. The profiles of turbulence intensity appeared to have minor deviations from the reported exponential decay profiles in the entire depth downstream of the boulder but only within a certain depth in the upstream and both sides of it. The correlation coefficient of velocity fluctuations was found to differ slightly from the reported exponential relation in the downstream and both sides of the boulder, whereas the difference was substantial in the upstream of it. Empirical relations were proposed for the profiles of streamwise mean velocity, turbulence intensity, and the correlation coefficient of velocity fluctuations. [ABSTRACT FROM AUTHOR]
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Database: Engineering Source
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Abstract:Boulders are widely used in fish habitat enhancement structures or fish passes. This study provides a detailed measurement of mean and turbulent flow around a boulder in a boulder array under a wake-interference flow condition. It was found that the vertical profiles of normalized streamwise mean velocity and streamwise turbulent intensity were approximately similar around the boulder, but both had different shapes in the upstream, downstream, and left and right sides of the boulder. The profiles of streamwise mean velocity deviated substantially from the classic logarithmic law but agreed with the Coles' wake law fairly well. The profiles of turbulence intensity appeared to have minor deviations from the reported exponential decay profiles in the entire depth downstream of the boulder but only within a certain depth in the upstream and both sides of it. The correlation coefficient of velocity fluctuations was found to differ slightly from the reported exponential relation in the downstream and both sides of the boulder, whereas the difference was substantial in the upstream of it. Empirical relations were proposed for the profiles of streamwise mean velocity, turbulence intensity, and the correlation coefficient of velocity fluctuations. [ABSTRACT FROM AUTHOR]
ISSN:07339429
DOI:10.1061/(ASCE)HY.1943-7900.0001273