Paper Number
SC4 

Session
Suspensions and Colloids

Title
Crossover scaling of shear-thickening in monodisperse and bidisperse suspensions

Presentation Date and Time
October 10, 2022 (Monday) 10:50

Track / Room
Track 1 / Sheraton 4

Authors (Click on name to view author profile)

  1. Chakraborty, Bulbul (Brandeis University, Martin Fisher School of Physics)
  2. Morris, Jeffrey F. (CUNY City College of New York, Levich Institute and Dept. of Chemical Engineering)
  3. Malbranche, Nelya (CUNY City College of New York, Levich Institute and Dept. of Chemical Engineering)
  4. Santra, Aritra (The City College of New York, CUNY, Levich Institute)

Author and Affiliation Lines (in printed abstract book)
Bulbul Chakraborty1, Jeffrey F. Morris2, Nelya Malbranche2 and Aritra Santra2
1Martin Fisher School of Physics, Brandeis University, Waltham, MA 02453; 2Levich Institute and Dept. of Chemical Engineering, CUNY City College of New York, New York, NY 10031

Speaker / Presenter 
Chakraborty, Bulbul

Keywords
theoretical methods; computational methods; colloids; jammed systems; suspensions

Text of Abstract
Crossover scaling is used to describe equilibrium behavior in systems with multiple critical points with distinct singular behavior, e.g. the Heisenberg-Ising magnetic spin system [1]. We use crossover scaling to consider suspension shear thickening, first showing that the Wyart & Cates model [2] of the lubricated-to-frictional transition can be recast in terms of crossover scaling, but with assumed equivalence of the singular response at the two critical points of frictionless and frictional jamming. Recent experiments analyzed by crossover scaling show that cornstarch and silica sphere suspensions obey the same scaling, with a somewhat weaker divergence of the viscosity at the frictional (high stress) than at the frictionless (low stress) jamming point [2]. We analyze simulations by the LF-DEM method of nearly monodisperse and significantly bidisperse (3:1 size ratio) suspensions. Good collapse of the rheological functions (viscosity and normal stresses) to a scaling form is found, but again with a weakening of the exponent of the viscosity divergence as the frictional jamming point is approach. After determining the appropriate jamming fractions for each set of packing parameters, the scaling collapse for bidisperse suspension shear and normal stress data to the form used for the monodisperse case is also surprisingly good, except when the large particles are a large predominance (85%) of the particle volume. The contribution of forces across the various types of contacts (e.g., large-large, large-small) provides some insight to this failure of scaling. [1] Cardy, J. 1996 Scaling and renormalization in statistical physics. Cambridge Univ. Press. [2] Wyart, M. and Cates, M.E. 2014 Phys. Rev. Lett. 112, p. 098302. [3] Ramaswamy, M. et al 2021 arXiv preprint arXiv:2107.13338.