Anomalous diffusion of inertial particles in random parallel flows: Theory and numerics face to face

The large-scale transport of inertial particles is investigated by means of Lagrangian simulations. Our main focus is on the possible emergence of anomalous diffusion for the class of random parallel flows. For such flows, a perturbative prediction in the limit of small inertia has recently become available in the literature. Anomalous diffusion was traced back to the possible divergence of the first-order correction to the eddy diffusivity of the tracer limit. Our numerical results show that the conditions for the emergence of anomalous diffusion are affected by resummations of higher-order perturbative contributions which regularize the resulting diffusion process, thus ruling out the occurrence of anomalous diffusion.