Author(s): Taka-Aki Okamoto; Iehisa Nezu; Aki Katayama
Linked Author(s): Iehisa Nezu
Keywords: Turbulent diffusion; Vegetation; Coherent vortices; LIF; PIV
Abstract: Aquatic plants in natural rivers are the essentially important components of many ecosystems and the submerged vegetation has the potential to improve water quality. Submerged canopies generate coherent vortices at the top of the canopy, which control the mass exchange between the within-canopy layer and the overcanopy layer. While the turbulent diffusion in emergent vegetated flows has been studied by some researchers, the effect of the submerged vegetation on mass transport has not been fully investigated. So, continuous dye-injection experiments were conducted to evaluate the vertical mass transport in open-channel flow with rigid vegetation models by changing the vegetation density. In the present study, a combination technique between particle image velocimetry (PIV) and planar laserinduced fluorescence (LIF) was developed to measure the turbulent diffusion property and the coherent motions simultaneously.
Year: 2009