THE EFFECT OF CROSS-STREAM TOPOGRAPHY ON THE INERTIAL EVOLUTION OF A COASTAL CURRENT

A potential-vorticity-conserving, channelled flow is investigated in t he presence of a step-like cross-stream topography, in order to simula te the behaviour of an idealized coastal current. This is performed by resorting to a truncated perturbative expansion of the vorticity equa tion that establishes the first-order correction of the upstream arbit rary flow. It is pointed out, in simple cases, the formation of a late ral intensification of the current in proximity of the step and the co nsequent, possible, instability of the downstream flow.