Vegetation in waterways plays an important role in channel evolution and morphodynamic processes (Jang & Shimizu, 2007). The presence of vegetation in flowing water affects the flow dynamics, water quality and self-purification, hydro-morphology, and habitat structure of aquatic lives (Nikora, 2010). Entering the 21st century, there have been increasing voices advocating vegetation in waterways for the purpose of protecting the channel bed and banks from erosion (Mars et al., 1999;Termini, 2015). Most attention in this area is currently paid to natural low-velocity monophase water flow interacting with underwater vegetation. Previous studies indicated that the effects of vegetation suppressed the growth and distribution of flow turbulence, which was closely linked to the vegetation density (
Chute aerators introduce a large air discharge through air supply ducts to prevent cavitation erosion on spillways. There is not much information on the microcosmic air bubble characteristics near the chute bottom. This study was focused on examining the bottom air-water flow properties by performing a series of model tests that eliminated the upper aeration and illustrated the potential for bubble variation processes on the chute bottom. In comparison with the strong air detrainment in the impact zone, the bottom air bubble frequency decreased slightly. Observations showed that range of probability of the bubble chord length tended to decrease sharply in the impact zone and by a lesser extent in the equilibrium zone. A distinct mechanism to control the bubble size distribution, depending on bubble diameter, was proposed. For bubbles larger than about 1-2 mm, the bubble size distribution followed a-5/3 power-law scaling with diameter. Using the relationship between the local dissipation rate and bubble size, the bottom dissipation rate was found to increase along the chute bottom, and the corresponding Hinze scale showed a good agreement with the observations.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.