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arXiv · 1703.01669

Relative velocities in bidisperse turbulent suspensions

J. Meibohm·L. Pistone·K. Gustavsson·B. Mehlig
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Abstract

We investigate the distribution of relative velocities between small heavy particles of different sizes in turbulence by analysing a statistical model for bidisperse turbulent suspensions, containing particles with two different Stokes numbers. This number, ${\rm St}$, is a measure of particle inertia which in turn depends on particle size. When the Stokes numbers are similar, the distribution exhibits power-law tails, just as in the case of equal ${\rm St}$. The power-law exponent is a non-analytic function of the mean Stokes number $\overline{\rm St}$, so that the exponent cannot be calculated in perturbation theory around the advective limit. When the Stokes-number difference is larger, the power law disappears, but the tails of the distribution still dominate the relative-velocity moments, if $\overline{\rm St}$ is large enough.

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J. Meibohm, L. Pistone, K. Gustavsson, B. Mehlig. 2017-07-18. Relative velocities in bidisperse turbulent suspensions. https://doi.org/10.1103/physreve.96.061102

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