A novel method to generate tidal-like bores in the laboratory

Laboratory experiments are reported where the analogue of a tidal bore is generated with a centimeter-scale local tidal range in a water channel. A discussion of the hydraulic regimes allows to set the experimental conditions to observe the bore. Temporal measurements of the free surface deformation with an acoustic sensor display an analogue of the tidal asymmetry met in nature between the ebb and the flood. Spatial measurements of the free surface deformation are performed with a laser sheet which delineates the interface thanks to the fluorescent re-emission of fluoresceine diluted in water. Afterwards, a parameter space is provided for the observation of a mini-bore with different hydrodynamical regimes (undular, undular–breaking, breaking) by showing the influence of the analogue local tidal range on the shape of the tidal wave. Finally, flow visualizations reveal the inner structure of the velocity profile of the mini-bore in the undular–breaking regime characterized by flow reversals.