2009/12/29 by Rodney L. Varley, R. L. Varley, Varley, R. L.
Engineering · Materials Science · Mathematics · Physics and Astronomy · #FOS: Physical sciences #Gas Dynamics and Kinetic Theory #Material Dynamics and Properties #Particle Dynamics in Fluid Flows #Statistical Mechanics (cond-mat.stat-mech) #cond-mat.stat-mech
paper · pdf · doi:10.48550/arxiv.0912.5365
9 pages; 1 figure
arxiv created 2009/12/29 · openalex publication_date 2009/12/29 · arxiv updated 2010/01/14 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Kim and Fedele discovered experimental evidence for the breakdown of the Millikan's Law for the fall rate of oil droplets in Nitrogen gas and the discrepancy is most pronounced for the smallest, sub-micron size particles. Here we explain these results by showing that the particle's motion is determined in part by the bare shear viscosity which is defined by the averaging length lambda. This is in contrast to the usual theory which involves the renormalized shear viscosity. An increase in gas pressure produces a decrease in the bare shear viscosity and as a result the fall rate increases. This behavior is opposite the Millikan Law prediction that an increase in pressure produces a decrease in fall rate. As a result, the bare shear viscosity is experimentally measurable by the fallrate. The theory here uses a convective diffusion equation and a Langevin approach will be presented elsewhere.