Research Projects

Charged suspension flows occur in natural and industrial settings, involving particle inertia, turbulence, surface phenomena, and electrostatic forces. The primary mode of charge separation is through contact electrification when particles collide. In turbulent flows, suspended particles are expelled from regions of high vorticity, leading to 'caustics' where particles with different velocities come together. Large relative velocities lead to enhanced collision rates between particles, which may resolve the 'droplet-growth bottleneck' in warm-rain initiation. The tribo-electric separation of charges is highly sensitive to surface properties, and the magnitude of charge and polarity of charging can depend on the surface properties of the particles colliding. The dependence of charge transfer on surface properties is a subject of ongoing research. The study proposes to study turbulent flows of mono- and bi-disperse suspensions using direct numerical simulation (DNs) of the Navier-stokes equations. The results will be applied to studying charging in thunderstorms and volcanic ash plumes, with particle stokes numbers and turbulent Reynolds numbers.