Joint statistics of acceleration and vorticity in fully developed turbulence

We report results from a high-resolution numerical study of fluid particles transported by a fully developed turbulent flow at R? = 280. Single-particle trajectories were followed for a time range spanning more than three decades, from less than a tenth of the Kolmogorov timescale up to one large-eddy turnover time. We present results concerning acceleration statistics and the statistics of trapping by vortex filaments conditioned to the local values of vorticity and enstrophy. We found that a suitable observable, a? = a × v, connected to the centripetal acceleration, is strongly sensitive to the trapping of particles into vortex filaments. In particular, we found that its sign may persist up to 10–15 t?, while the typical oscillation of the longitudinal acceleration happens on a time lag of a few t?.