2019/09/25 by Merlin A. Etzold, Etzold, Merlin A., Julien R. Landel +3
Engineering · #FOS: Physical sciences #Fluid Dynamics (physics.flu-dyn) #Fluid Dynamics and Turbulent Flows #Heat and Mass Transfer in Porous Media #Particle Dynamics in Fluid Flows
paper · pdf · doi:10.48550/arxiv.1909.11658
openalex publication_date 2019/09/25 · openalex created_date 2022/07/28 · openalex updated_date 2026/07/28
We study the steady laminar advective transport of a diffusive passive scalar\nreleased at the base of narrow three-dimensional longitudinal open channels\nwith non-absorbing side walls and rectangular or truncated-wedge-shaped\ncross-sections. The scalar field in the advective--diffusive boundary layer at\nthe base of the channels is fundamentally three-dimensional in the general\ncase, owing to a three-dimensional velocity field and differing boundary\nconditions at the side walls. We utilise three-dimensional numerical\nsimulations and asymptotic analysis to understand how this inherent\nthree-dimensionality influences the advective-diffusive transport as described\nby the normalised average flux, the Sherwood Sh or Nusselt numbers for mass\nor heat transfer, respectively. We show that Sh is well approximated by an\nappropriately formulated two-dimensional calculation, even when the boundary\nlayer structure is itself far from two-dimensional. This important result can\nsignificantly simplify the modelling of many laminar advection--diffusion\nscalar transfer problems: the cleaning or decontamination of confined channels,\nor transport processes in chemical or biological microfluidic devices.\n