Multiscale particle motion in rotating turbulence

Using Direct Numerical Simulations (DNS) and theory, we examine the multiscale motion of particles (with and without inertia) in rotating turbulence. Rapid rotation affects particle motion directly, through Coriolis and centrifugal forces, and also indirectly through the way it modifies the spatiotemporal structure of the turbulence. The DNS are designed to enable exploration of particle motion in both the Zeman regime (where Zeman phenomenology is expected to hold) and the inverse cascade regime of the flow. Asymptotic predictions for the particle relative dispersion in the plane normal to the rotation axis are derived for both the Zeman and inverse cascade regimes, capturing the leading order effects of particle inertia at these scales. For fluid particles, the results show that rotation leads to strong anisotropy of their relative dispersion, with dispersion parallel to the rotation axis being not only smaller, but also growing much more slowly in time than that in the plane normal to rotation. Further, high-order moments of the dispersion show a suppression of extreme events in the relative dispersion in the parallel direction due to rotation. We also find that in certain regimes, particle inertia leads to some unexpected modifications to the relative dispersion behavior.