Hydrodynamic Instabilities in Open-Channel Flow past Lateral Cavities

Abstract

The hydrodynamic instabilities of open-channel flow past sequential lateral cavities were physically modelled in a relatively large facility. The range of free-surface oscillation was about one third of the mean water depth. High-frequency sampling of free-surface elevations confirmed the existence of fluctuations at a quasi-constant frequency, less than that of gravity standing waves. The trajectories of neutrally-buoyant particles were recorded within a cavity. The data showed a wide range of residence times with complicated motion patterns. The current study emphasised the effect of full-height sidewall baffles on open-channel flow instabilities while further analyses need to be performed to provide reference for the design of baffled waterways.