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Title: Modeling and Algorithmic Approaches to Constitutively-Complex, Micro-structured Fluids

The team for this Project made significant progress on modeling and algorithmic approaches to hydrodynamics of fluids with complex microstructure. Our advances are broken down into modeling and algorithmic approaches. In experiments a driven magnetic bead in a complex fluid accelerates out of the Stokes regime and settles into another apparent linear response regime. The modeling explains the take-off as a deformation of entanglements, and the longtime behavior is a nonlinear, far-from-equilibrium property. Furthermore, the model has predictive value, as we can tune microstructural properties relative to the magnetic force applied to the bead to exhibit all possible behaviors. Wave-theoretic probes of complex fluids have been extended in two significant directions, to small volumes and the nonlinear regime. Heterogeneous stress and strain features that lie beyond experimental capability were studied. It was shown that nonlinear penetration of boundary stress in confined viscoelastic fluids is not monotone, indicating the possibility of interlacing layers of linear and nonlinear behavior, and thus layers of variable viscosity. Models, algorithms, and codes were developed and simulations performed leading to phase diagrams of nanorod dispersion hydrodynamics in parallel shear cells and confined cavities representative of film and membrane processing conditions. Hydrodynamic codes for polymeric fluids aremore » extended to include coupling between microscopic and macroscopic models, and to the strongly nonlinear regime.« less
Authors:
 [1]
  1. University of North Carolina at Chapel Hill
Publication Date:
OSTI Identifier:
1130460
Report Number(s):
DOE-UNC-01914
DOE Contract Number:
SC0001914
Resource Type:
Technical Report
Research Org:
University of North Carolina at Chapel Hill
Sponsoring Org:
USDOE
Contributing Orgs:
Lawrence Berkeley National Laboratory, University of California at Davis
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS