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DY: Fachverband Dynamik und Statistische Physik
DY 48: Granular Matter and Contact Dynamics
DY 48.4: Talk
Thursday, March 21, 2024, 15:45–16:00, BH-N 128
How to make Sense of Fluidized Bed Rheology using Shear Banding and Three Time Scales — •W. Till Kranz1,2, Olfa D’Angelo2,3, Olivier Coquand2,4, Abhishek Shetty5, and Matthias Sperl2,1 — 1University of Cologne, Germany — 2DLR, Germany — 3University of Erlangen, Germany — 4University of Perpignan, France — 5Anton Paar, USA
The rheology of granular fluids is surprisingly rich if agitation by
shear is combined with fluidization and comprises ordinary Newtonian
rheology as well as shear thinning and shear thickening regimes. We
will report on careful measurements of air-fluidized glass beads in a
Taylor-Couette shear cell [1]. We will sketch a procedure to extract
quantitative rheological information spanning all the rheological
regimes and summarized in only a handful of physically meaningful
parameters. Taking into account shear banding this approach embraces
and extends the well known empirical µ-I-rheology [2]
of non-fluidized granular flows. Using simple arguments involving
three relevant time scales, we will show how the seemingly complex
rheology stems from intuitive and transparent physical principles [3].
[1] O. D’Angelo, A. Shetty, M. Sperl and W. T. Kranz, arXiv:2309.00413
[2] GDR Midi, EPJ E 14, 341 (2004)
[3] O. Coquand, W. T. Kranz and M. Sperl, arXiv:2008.05931
Keywords: Granular Fluid; Fluidized Bed; Rheology; Integration Through Transients