Vortical structures of trajectories and transport of tracers advected by turbulent fluids

摘要

Tracer transport in two-dimensional incompressible turbulent fluids is studied using the nested subensemble method, a semi-analytical statistical approach. Quasi-coherent vortical structures of trajectories are shown to appear when the stream function has slow time variation. In the presence of weak perturbation the structures are not destroyed and they determine anomalous transport regimes.