MICROSCOPIC-SCALE SIMULATIONS OF MACROSCOPIC FLOW PATTERNS IN NONEQUILIBRIUM 2-DIMENSIONAL SYSTEMS

We have used a molecular-dynamics simulation for reproducing the behav iour of a two-dimensional fluid flow submitted to external perturbatio ns and embedded in a non-inertial reference frame. This simple model h as been used to verify current hypotheses on the causes generating a c yclonic circulation in the North Tyrrhenian basin, provided one uses s uitable perturbation strenghts scaled from the real-world dynamics. Re sults put in evidence that the onset of a stationary cyclonic circulat ion which superimposes to the S-N flow requires the simultaneous prese nce of an orthogonal and an anti-parallel stream. This finding is in a greement with the hypotheses suggested by a preliminary analysis of ex perimental data. The limits of such models are discussed together with possible extensions to reproduce mesoscopic systems, in order to simu late the coexistence of large- and small-scale dynamics. The model is particularly suited to deal with boundary conditions of general analyt ical shapes.