Modelling of the sedimentation phenomenon of solid particles immersed in a turbulent fluid

Settling phenomenon of solid particles immersed in a turbulent fluid has been investigated, in a condition of free-stream turbulence. Since structures formed onto this condition are complex, it is difficult to predict exactly how particles move. It is thus appropriate to conduct deepen studies of the phenomenon and carry out simulations to describe particles’ settling velocity. In order to define a new correlation for the evaluation of particles’ settling velocity, different literature correlations and parameters have been exploited. Langevin dynamics has been used to describe fluid’s motion, and by considering several forces acting on particles (buoyancy, drag, gravitational and virtual mass), it has been possible to evaluate their settling velocity, through a computational approach. Data have been obtained by varying characteristic properties, such as kinetic energy, its rate of dissipation, and physical properties of fluid and particles. Aiming to find a reliable correlation which best explains the settling phenomenon, results in output from simulations have been compared with that deriving from proposed correlation. Encouraging results have been obtained over the range of operating conditions examined.