Abstract
In the literature, two different frameworks exist for describing the rheology of solid/liquid suspensions: (1) the “viscous” framework in terms of the relative suspension viscosity, η_{r}, as a function of the reduced solid volume fraction, f=f_{m}, with f_{m} the maximum flowable packing fraction, and (2) the “frictional” framework in terms of a macroscopic friction coefficient, μ, as a function of the viscous number, I_{v}, defined as the ratio of the viscous shear to the wallnormal particle stress. Our goal is to compare the two different frameworks, focusing on the effect of friction between particles. We have conducted a particleresolved direct numerical simulation study of a dense nonBrownian suspension of neutrally buoyant spheres in slow plane Couette flow. We varied the bulk solid volume fraction from f_{b} ¼ 0:1 to 0.6 and considered three different Coulomb friction coefficients: μ_{c} ¼ 0, 0.2, and 0.39. We find that η_{r} scales well with f=f_{m}, with f_{m} obtained from fitting the Maron–Pierce correlation. We also find that μ scales well with I_{v}. Furthermore, we find a monotonic relation between f=f_{m} and I_{v}, which depends only weakly on μ_{c}. Since η_{r} ¼ μ=I_{v}, we thus find that the two frameworks are largely equivalent and that both account implicitly for Coulomb friction. However, we find that the normal particle stress differences, N_{1} and N_{2}, when normalized with the total shear stress and plotted against either f=f_{m} or I_{v}, remain explicitly dependent on μ_{c} in a manner that is not yet fully understood.
Original language  English 

Pages (fromto)  263283 
Number of pages  21 
Journal  Journal of Rheology 
Volume  68 
Issue number  2 
DOIs  
Publication status  Published  2024 
Funding
The authors gratefully acknowledge Delft University of Technology, the funding of this project under a TU Delft/TNO agreement, and the support of SURF Cooperative for the use of the Dutch national einfrastructure (Snellius) under Computing Grant No. 2020.036 from the Dutch Research Council (NWO).Fingerprint
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Data corresponding to the publication: "Interparticle friction in sheared dense suspensions: Comparison of the viscous and frictional rheology descriptions"
Peerbooms, W. (Creator), Nadorp, T. (Creator), van der Heijden, A. E. D. M. (Creator) & Breugem, W. P. (Creator), TU Delft  4TU.ResearchData, 4 Mar 2024
DOI: 10.4121/bbb1d55372304a6080a223d5697d89a5
Dataset/Software: Dataset