Statistics of particle diffusion subject to oscillatory flow in a porous bed

An experimental study was conducted of particle diffusion within a porous bed when exposed to oscillatory flow. The particle oscillates up and down within the porous bed in response to the oscillatory flow, but also becomes intermittently stuck for time intervals of varying duration. The combination of oscillating flow and random hindering of the particle motion by the porous bed leads to a diffusive process called oscillatory diffusion. A variety of statistical measures are used to characterize the particle diffusion under the oscillatory flow. These measures show that the experimental data exhibit characteristics of both classical diffusive processes as well as oscillatory processes. The particle hold-up time duration was found to be well fit by a log-normal distribution for all experimental cases examined. A simple stochastic model that captures the key features of the oscillatory diffusion process is shown to yield statistical measures that compare well with experimental data. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

An experimental study on particle diffusion within a porous bed under oscillatory flow conditions showed that particles oscillate and become intermittently stuck, leading to a diffusive process called oscillatory diffusion. Statistical measures revealed characteristics of both classical diffusive processes and oscillatory processes, with the particle hold-up time duration fitting a log-normal distribution. A simple stochastic model of the oscillatory diffusion process yielded statistical measures that matched well with experimental data.