Charged particle dynamics in turbulence: Theory and direct numerical simulations

The presence of electrostatic charge can significantly alter the collision rate of inertial particles in turbulence. The influence of charge on the particle radial relative velocity and on the radial distribution function is investigated through direct numerical simulations of homogeneous, isotropic turbulence containing Lagrangian point particles. Particles with opposite charge polarity have enhanced inward radial relative velocity and radial distribution function, both increasing with decreasing separation distance. For like-charged particles, the converse is generally true. A simplified model for the influence of charge on relative velocity and radial spatial distribution is found to capture the general behavior. The model is based on the assumption of the superposition of relative velocity arising for charged particles in still fluid, and relative velocity arising from dissipation-scale turbulent velocity fluctuations.