Effect of particle orientation on the drag force in random arrays of oblate ellipsoids inlow-Reynolds-number flows

Through particle-resolved direct numerical simulations of flows past random arrays of oblate ellipsoids at low Reynolds numbers, this work demonstrates how the drag force on oblate ellipsoids depends on the Hermans orientation factorS, the mean crosswise sphericity phi(perpendicular to), the aspect ratioAR, and the solid volume fractionc. Wide ranges ofS,AR, andcare considered and they are in the intervals (-0.5, 1), (0.2, 0.8), and (0.1, 0.4), respectively. This study extends the work on prolate ellipsoids by Li et al (AIChE Journal, 2019, 65, e16621). Based on the simulation results, two models are respectively developed usingSand phi(perpendicular to)as the independent orientation factor. The model based onScould give accurate prediction of the drag force and the lateral force exerted on arrays of particles. The model based on phi(perpendicular to)is able to use one generalized drag correlation for both oblate and prolate ellipsoids.

Automated summary

This study investigates the drag force on oblate ellipsoids in random arrays using direct numerical simulations, considering factors such as Hermans orientation factor, mean crosswise sphericity, aspect ratio, and solid volume fraction. Two models are developed based on different orientation factors for accurate prediction of drag force and lateral force.