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Clustering and collisions of heavy particles in random smooth flows

J. Bec·A. Celani·M. Cencini·S. Musacchio
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Abstract

Finite-size impurities suspended in incompressible flows distribute inhomogeneously, leading to a drastic enhancement of collisions. A description of the dynamics in the full position-velocity phase space is essential to understand the underlying mechanisms, especially for polydisperse suspensions. These issues are here studied for particles much heavier than the fluid by means of a Lagrangian approach. It is shown that inertia enhances collision rates through two effects: correlation among particle positions induced by the carrier flow and uncorrelation between velocities due to their finite size. A phenomenological model yields an estimate of collision rates for particle pairs with different sizes. This approach is supported by numerical simulations in random flows.

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J. Bec, A. Celani, M. Cencini, S. Musacchio. 2005-08-05. Clustering and collisions of heavy particles in random smooth flows. https://doi.org/10.1063/1.1940367

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