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Effect of Aquatic Vegetation on Gas Transfer Velocity in Open-Channel Flows

Author(s): Takaaki Okamoto; Michio Sanjou

Linked Author(s): Michio Sanjou

Keywords: No Keywords

Abstract: The present study investigates the effects of the aquatic vegetation on the surface-velocity divergence (SD) to develop physical modelling of gas transfer mechanism in natural rivers. Velocity and gas concentration measurements were carried out to reveal gas transfer phenomena in open-channel flows and vegetation flows. A large-scale coherent vortex appears near the vegetation top due to the shear instability, and the submerged vegetation was found to promote the gas transfer beneath air/water interface. Furthermore, we revealed that the gas transfer velocity increases with an increase of the vegetation density. We proposed a new surface divergence model with wide generality, which is applicable uniformly to the open-channel flows and the mixing layer flows with aquatic canopy.


Year: 2018

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