Transition to turbulence in randomly arranged porous media is observed in nature and industrial applications. The flow characteristics of these flows during transition are not well identified from the perspective of vortical structures generation and break up. This work describes the parameters influencing the overall mixing during the transition process from the perspective of scale of vortical structures and dispersion characteristics by addressing the following questions: (a) what are the dominant mechanisms of evolution of the scale of vortices, and (b) how does the inertial effects of vortical structures enhance the flow transport properties through tortuosity and dispersion. Time-resolved PIV is used to investigate the flow in the macro-scale Reynolds numbers from 100 to 1000 to show the pore- versus macro-scale effects on the scale of the flow dispersion, and their contribution in interpreting the overall flow mixing. A model is developed to find the dispersion coefficient from Eulerian PIV data sets. Lagrangian mixing characteristics derived from Eulerian local pore velocity variances is used to demonstrate the bed characteristics for flow in randomly distributed porous media flows. The dispersion asymptotically approaches 0.085% of VintDH longitudinally which shows that the turbulent transport is increased by enhancing the Reynolds number that matches very well with results in the literature.

Vortical Structures and Mixing Characteristics of Flow in Randomly Packed Porous Media During Transition to Turbulence

Paper Proceedings: https://asmedigitalcollection.asme.org/FEDSM/FEDSM2021/volume/85284

ASME 2021 Fluids Engineering Division Summer Meeting (FEDSM2021)

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