Particle resuspension in turbulent flow: A stochastic model for individual soil grains

A stochastic model for the motion of a particle initially at rest on a surface is explored. Fluid and adhesive forces are quantified based on first principles, and turbulent fluctuations are addressed probabilistically from probability distribution functions. A Monte Carlo process yields the distributions of particle position and velocity under a wide range of wind conditions and soil sizes. Results indicate that particle size and friction velocity are the most important factors in determining if a particle will resuspend and in predicting its subsequent motion. Larger wind speeds produce more violent fluctuations, which have a greater effect on small particles than on large particles. A theoretical analysis of the threshold friction velocity supports earlier experimental findings. The aerodynamic lift force cannot be neglected, and the torque exerted on a particle can be important in some cases. Applying the results of this work may contribute to reducing uncertainty in large-scale aerosol models.