title: Settling statistics of hard sphere particles.
abstract: Direct imaging of settling, non-Brownian, hard sphere, particles allows measurement of particle occupancy statistics as a function of time and sampling volume dimension. Initially random relative particle number fluctuations, <N2-<N>(2)>/<N> = 1, become suppressed, anisotropic, and <N> dependent. Fitting to a simple Gaussian pair correlation model suggests a minute long ranged correlation leads to strong if not complete suppression of number fluctuations. Calflisch and Luke predict a divergence in velocity fluctuations with increasing sample volume size based on random (Poisson) statistics. Our results suggest this is not a valid assumption for settling particles.
authors.affiliation: Department of Physics, Oklahoma State University, Stillwater, OK 74078-3072, USA.
authors.forename: X
authors.initials: X
authors.lastname: Lei
authors.forename: B J
authors.initials: BJ
authors.lastname: Ackerson
authors.forename: P
authors.initials: P
authors.lastname: Tong