Abstract
Large roughness elements such as boulders have a considerable effect on surrounding mean and turbulent flow, which can lead to modifications in local sediment transport and instream habitat quality. Understanding the difference between the flow field around an individual boulder and a boulder within a boulder array can determine the degree of influence of boulder arrays on surrounding flow fields. This experimental study compared the mean and turbulent flow fields in the vicinity of an individual natural boulder, with a boulder within an array of boulders. The results showed the partial inability of the common exponential decay functions to describe turbulence intensities around the boulder. Higher turbulence intensities were observed in the wake of the single boulder. In presence of boulders, turbulent kinetic energy (TKE) profiles deviated from the profiles of an undisturbed flow, and this deviation extended to a further distance for the individual boulder case. Boulder array resulted in reduction of the Reynolds shear stress (RSS) values near the bed compared to the individual boulder. The results may provide helpful information for projects that use the instream boulder placement method such as stream restoration and natural fish passage projects.
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Pierce, R., Golpira, A., Baki, A.B.M. (2022). A Comparative Study of Mean and Turbulent Flow Fields Around a Boulder Within Boulder Array and an Individual Boulder. In: Walbridge, S., et al. Proceedings of the Canadian Society of Civil Engineering Annual Conference 2021 . CSCE 2021. Lecture Notes in Civil Engineering, vol 250. Springer, Singapore. https://doi.org/10.1007/978-981-19-1065-4_29
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DOI: https://doi.org/10.1007/978-981-19-1065-4_29
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