Study and simulation of the movement and settlement of particles smaller than 200 microns under various wind velocities using Fluent software

Dust storm and its mitigation require in-depth knowledge of prevailing parameters and their interaction. Accordingly, study of dust storm motion and its deposition have special significance. Among the dust storm studying methods, simulation is important because of its lower cost and independency on experiment or satellite. The goal of this study was to simulate the motion and deposition of clay dust storm particles with size of 0.001 to 200 micron affected by wind speed of 1, 3, 10 and 20 m.s-1 on a smooth land and hypothetic obstacles with a height of 6 and 12 m. Gambit and Fluent are used for creating the simulation environment and solving the continuity and Navier-Stokes equations coupled with turbulence intensities equations. According to the results, wind speed is a negative factor for dust storm particle deposition on earth and obstacle surfaces and it is independent of the obstacle height. Therefore, particles under one micron remain primarily in the air and they deposit lower than 10 percent, so they can transfer to farther distances. The larger the particles, the more efficient the gravitational mechanism in their deposition phenomena; such a way that the deposition calculated more than 30 percent for particles larger than 100 microns. At the same wind speed and particle size, the 12m obstacle postpones the deposition because of the separation of the flow from the surface and turbulence and it also decreases the deposition of particles under micron to lower than 1 percent. The deposition of these particles doesn’t vary with wind speed but the one for particles larger than 10 micron is inversely proportional with wind speed.