How do neighbors affect incipient particle motion in laminar shear flow?

Rodríguez Agudo J, Dasilva S, Wierschem A (2014)

Publication Type: Journal article

Publication year: 2014


Publisher: American Institute of Physics (AIP)

Book Volume: 26

Pages Range: 053303

Journal Issue: 5

DOI: 10.1063/1.4874604


We experimentally study how neighboring particles affect the incipient motion of particles on regular substrates and exposed to a laminar shear flow. To this end, we determine the critical Shields number and determine whether the particle rolls or slides. The substrates consist of a monolayer of fixed spheres of uniform size that are regularly arranged in triangular and quadratic configurations. Neighboring particles influence the incipient motion by shielding to the shear flow and may inhibit continuous motion once they are in direct contact with the particle. At the low particle Reynolds numbers studied, neighboring spheres on themonolayer only affect the incipient particle motion if they are closer than about 3 particle diameters. Direct contact inhibits continuous motion and results in a strong increase of the critical Shields number. For identical beads, we found two different regimes for the onset of continuous motion. Depending on the substrate geometry, the upstream particle may start to roll like a single particle passing the downstream neighbor or it may push its downstream neighbor forward. In the latter case, the downstream sphere rolls while the upstream bead slides in contact with the downstream neighbor. Both regimes yield about the same critical Shields number although the critical Shields number for single particle motion differs by about 50%. If particle contact is avoided by a sudden jump in the Shields number, the critical Shields number for onset of continuous particle motion can be reduced considerably. Finally, the lowest critical Shields numbers for dislodging buried beads in the configurations studied coincides with the critical Shields number for incipient motion of irregular granular beds. C © 2014 AIP Publishing LLC.

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Rodríguez Agudo, J., Dasilva, S., & Wierschem, A. (2014). How do neighbors affect incipient particle motion in laminar shear flow? Physics of Fluids, 26(5), 053303.


Rodríguez Agudo, José, S. Dasilva, and Andreas Wierschem. "How do neighbors affect incipient particle motion in laminar shear flow?" Physics of Fluids 26.5 (2014): 053303.

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