Estimating the Collision Rate of Inertial Particles in a Turbulent Flow: Limitations of the ‘Ghost Collision’ Approximation

Voßkuhle M, Pumir A, & Lévêque E

Journal of Physics: Conference Series, vol. 318, no. 5, p. 052024, 2011. DOI: 10.1088/1742-6596/318/5/052024.

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Most studies of collisions in turbulent flows are based on the ghost collisionapproximation, whereby one follows a number of particles, and simply counts the number of times the distance between two particles becomes less than the sum of their radii; particles are kept in the flow after they collided. We discuss here the limitations of this approximation, and demonstrate, using a simple model flow, that it leads to overestimates of the real collision rate by as much as  ∼ 30 % at small Stokes numbers.