27/09/2024 - Maria Rita Maggi
We present experimental results of stratified exchange flows in a rotating frame in interaction with a bottom sediment bed, revealing the intricate interactions between main and secondary flow and the morphodynamics. This system is representative of deltas, lagoons and estuaries which are transitional environments often in precarious equilibrium under present climate. We show that the sediment transport is driven mainly by Ekman dynamics with a net transport across the channel cross-section in direction of the geostrophic slope. The model for sediment suspension given in Maggi et al. (2024) is adapted including the across channel sediment transport and employed to predict the spatial evolution of sediment concentration. At higher rotation rates, baroclinic instability produces columnar vortices whose characteristics compare well with Pedlosky’s theory, and induces the meandering of the bottom salty layer, with preferential erosion patterns.