Structure and dynamics of electrorheological fluids
- Advanced Materials Physics Division, Sandia National Laboratories, Albuquerque, New Mexico 87185-1421 (United States)
- Exxon Research and Engineering, Route 22 East, Annandale, New Jersey 08801 (United States)
- Department of Physics, University of Pennsylvania, Philadelphia, Pennsylvania 19104 (United States)
We have used two-dimensional light scattering to study the structure and dynamics of a single-scattering electrorheological fluid in the quiescent state and in steady and oscillatory shear. Studies of the quiescent fluid show that particle columns grow in two stages. Particles first chain along the electric field, causing scattering lobes to appear orthogonal to the field, and then aggregate into columns, causing the scattering lobes to move to smaller angles. Column formation can be understood in terms of a thermal coarsening model we present, whereas the early-time scattering in the direction parallel to the field can be compared to the theory of line liquids. In simple shear the scattering lobes are inclined in the direction of fluid vorticity, in detailed agreement with the independent droplet model of the shear thinning viscosity. In oscillatory shear the orientation of the scattering lobes varies nonsinusoidally. This nonlinear dynamics is described by a kinetic chain model, which provides a theory of the nonlinear shear rheology in arbitrary shear flows. {copyright} {ital 1998} {ital The American Physical Society}
- OSTI ID:
- 567027
- Journal Information:
- Physical Review. E, Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics, Journal Name: Physical Review. E, Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics Journal Issue: 1 Vol. 57; ISSN PLEEE8; ISSN 1063-651X
- Country of Publication:
- United States
- Language:
- English
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