Numerical Experiments of Uni- And Bi-Directional Exchange Flows in A Rotating Trapezoidal Sill-Channel

Results are presented for new laboratory-scale numerical simulations of uni- and bi-directional stratified flows generated within an idealized trapezoidal channel topography, as representative of net-barotropic exchange flows generated through sea straits between water masses with different densities. These simulations utilise the Bergen Ocean Model (BOM), a three-dimensional general ocean circulation model, both in non-rotating and rotating frames of reference. The results from the BOM simulations are aimed at simulating the large-scale experimental data obtained in the LEGI Coriolis rotating platform in Grenoble, within which velocity and density fields for exchange flows were measured through particle image velocimetry (PIV) and micro-conductivity density probes, respectively. The BOM simulations are shown to reproduce the main dynamic flow patterns and trends of the large-scale exchange flows through the trapezoidal channel, with the lower layer saline intrusion flux shown to reduce (i.e. due to partial blockage) as the upper freshwater flow is increased. These simulations represent preliminary numerical results and we expect that future simulations will improve overall representation of the interfacial region between the counter-flowing layers, and thus be relevant to many exchange flows generated in wide estuaries, sea straits and deep-ocean channels.