Experimental study of internal mixing and near-bed dynamics induced by restricted stratified exchange flows

This paper presents details of an experimental study investigating internal flow and near-bed dynamics induced by restricted exchange flows over idealized, scaled obstructions, representing both submerged estuarine sand bars and fjordic sills. The experiments are being performed within a specially constructed rectangular channel sited within the new large diameter Coriolis Rotating Platform II at LEGI Grenoble. Both rigid and erodible obstructions, having idealized trapezoidal cross-section with smoothed edges, will be considered. Experimental measurements will focus on obtaining high-resolution velocity and density profiles in the vicinity of obstruction to observe and quantify the internal mixing and near-bed dynamics generated by exchange flows under both rotating and non-rotating conditions. It is anticipated that this study will result in improved understanding of parametric controls on interfacial mixing and entrainment/detrainment processes for restricted exchange flows in silled fjordic basins, as well as boundary layer processes associated sediment transport and bed morphological changes encountered in semi-enclosed estuaries.