Localization-delocalization transitions in turbophoresis of inertial particles

Abstract

Small aerosols drift down temperature or turbulence gradient since faster particles fly longer distances before equilibration. That fundamental phenomenon, called thermophoresis or turbophoresis, is widely encountered in nature and used in industry. It is universally believed that particles moving down the kinetic energy gradient must concentrate in minima (say, on walls in turbulence). Here we show that this is incorrect: escaping minima is possible for inertial particles whose time of equilibration is longer than the time to reach the minimum. The best way out is always through: particles escape by flying through minima or reflecting from walls. We solve the problem analytically and find the phase transition as a sign change of the mean velocity. That means separation: light particles concentrate in a minimum while heavy particles spread away from it (gravity can reverse the effect). That discovery changes understanding of that fundamental phenomenon and may find numerous applications.

arXiv comment5 pages

References in corpus (7)

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• (1+1)-dimensional turbulence
• Turbulent Diffusion and Turbulent Thermal Diffusion of Aerosols in Stratified Atmospheric Flows
• Thermophoresis of Brownian particles driven by coloured noise
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• On phoretic clustering of particles in turbulence
• Relative velocities in bidisperse turbulent suspensions
• Preferential Sampling of Elastic Chains in Turbulent Flows
• Drag enhancement in a dusty Kolmogorov flow
• Phoresis in turbulent flows
• Phase transitions in the distribution of inelastically colliding inertial particles
• Localization-delocalization transition for light particles in turbulence
• Inelastic accretion of inertial particles by a towed sphere
• Inelastic collapse and near-wall localization of randomly accelerated particles
• Eddy diffusivity of quasi-neutrally-buoyant inertial particles
• Kinetic theory based solutions for particle clustering in turbulent flows