Author(s): R. A. Denton

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Abstract: The flow regimes for three-layer unidirectional flow over a bottom hump are classified using a graduallyvarying flow model. For the particular case of three-layer flow with fixed flowrates in each layer, there are ten possible flow regimes, each representing a different set of locations for the hydraulic controls. Unidirectional three-layer flow has one control for each of the three wave speeds: first- and second-mode internal wave and free-surface wave. A solution for three-layer flow through a contraction is also presented. Transitions between flow regimes are determined by comparing local maxima and minima in the variation of lower layer energy with layer thickness at key cross-sections. Experimental data show that the graduallyvarying (low model is able to successfully predict the actual interface and free-surface profiles except when the main control at the hump is an approach control. Solutions for three-layer flow at a first-mode crest control are used to illustrate the expected behaviour of multi-layered or continuously-stratified flow at a first-mode control.

DOI: https://doi.org/10.1080/00221689009499087

Year: 1990