SINGLE-PARTICLE TRAJECTORIES IN 2-DIMENSIONAL TURBULENCE

We study two-dimensional turbulence from a Lagrangian point of view, b y integrating the motion of an ensemble of passively advected particle s in the velocity field provided by numerical simulations of forced Na vier-Stokes equations in two space dimensions. The role of coherent st ructures is addressed and a summary of recent results on this problem is given. We discuss the statistical properties of single-particle tra jectories in 2D turbulence and study their scaling and fractal behavio ur. The preliminary results reported here indicate that particle paths in 2D turbulence seem to display a fractal nature characterized by a correlation dimension D-2 approximate to 1.3. This value of the dimens ion is similar to that observed for drifter trajectories in ocean flow s.