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Jason E. Butler
Associate Professor
Ph.D., 1998, The University of Texas at Austin
Dynamics of Complex Fluids
Suspension and Multiphase Fluid Mechanics
Polymer Dynamics
| Email: |
butler@che.ufl.edu |
| Phone: |
(352) 392-2591 |
| Fax: |
(352) 392-9513 |
| 431
Chemical Engineering Building |
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Brief Description of Current Research
My research group
primarily focuses on the dynamics of complex fluids. Complex fluids,
which include emulsions, colloidal and non-colloidal suspensions of
particulates, and polymeric solutions and melts, serve important roles
in biotechnology, materials science, and a wide range of existing and
emerging industrial technologies.
Efficient control and
processing of these materials requires an understanding of their
transport properties; yet complex fluids often demonstrate unexpected
and intriguing behavior under flow. The state of a complex fluid can be
characterized by the microstructure, or configuration and spatial
arrangement of the individual droplets within an emulsion or particles
within a suspension. A balance of forces governs the microstructure,
where the forces can include electro-magnetic interactions, surface
forces, thermal fluctuations, and others. Fluid flow introduces
additional forces which induce dynamic changes in the microstructure;
correspondingly, the flow field is a function of the microstructure.
This coupling between the flow field and the microstructure often
results in non-linear rheology and ensures that the dynamics of the
fluids are indeed “complex”.
To address these
problems one must develop a thorough understanding of the dynamics of
complex fluids. We are undertaking studies of specific complex systems
using a variety of methods. Experimental studies using advanced imaging
methods provide data on the relationship between the microstructure and
flow fields. Theoretical calculations and efficient computational
methods result in additional information and insight which cannot always
be obtained from experiments. Finally, a synthesis of the results from
all of these approaches will lead us to improved macroscopic models
describing the dynamics of complex fluids.
Current work focuses on
eliminating the disparity between quantitative predictions and
measurements of the equilibrium and viscoelastic properties of
suspensions of Brownian rods and rigid polymers. We are studying the
dynamics of these complex fluids using advanced simulation methods and
experimental techniques such as rheology, microrheology, and
light-scattering measurements. The expected improvements in methods and
theories used for the evaluation of complex fluids composed of rigid
polymers and Brownian fibers will impact existing and emerging
technologies in polymer science, nanotechnology, and biotechnology.
Other current work
encompasses improved simulation techniques for polymer systems and
research on the dynamics of non-Brownian suspensions. This includes
development of an algorithm for simulating polymers at a more detailed
level of description than is usually applied within Brownian dynamics
techniques. Also, the lattice-Boltzmann method has been adapted to
simulate polymer systems at a mesoscopic scale. The results have
allowed for an unprecedented simulation of polymers with hydrodynamic
interactions with on the order of 1000's of beads within a bead-spring
chain. The method is flexible enough to allow simulation of confined
polymers within nearly arbitrary geometries. In another project,
simulations and rheological studies are being performed to determine the
origin of anomalous migration for oscillating flows of particle
suspensions.
Selected Publications
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"Brownian dynamic simulations of concentrated suspensions of rigid
fibers: Relationship between short-time diffusivities and the long-time
rotational diffusion," P.D. Cobb and J.E. Butler, J. of Chemical
Physics, 123-054908 (2005).
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“Lattice-Boltzmann simulations of the dynamics of polymer solutions in
periodic and confined geometries'', O. Berk Usta, A.J.C. Ladd, and Jason
E. Butler, Journal of Chemical Physics, Vol. 122, #094902 (2005).
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“Brownian dynamics simulations of a flexible polymer chain which
includes continuous resistance and multi-body hydrodynamic
interaction'', Jason E. Butler and Eric S.G. Shaqfeh, Journal of
Chemical Physics, Vol. 122, #014901 (2005).
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“Drop
breakup in the flow through fixed fiber beds: An experimental and
computational investigation”, Prateek D. Patel, Eric S.G. Shaqfeh, Jason
E. Butler, Vittorio Cristini, Jerzy Blawzdziewicz, and Michael
Loewenberg, Physics of Fluids, Vol. 15, 1146-1157 (2003).
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“Dynamic
simulations of the inhomogeneous sedimentation of rigid fibers”, Jason
E. Butler and Eric S.G. Shaqfeh, Journal of Fluid Mechanics, Vol.
468, 205-237 (2002).
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“Inverse
method for imaging a free surface using electrical impedance
tomography”, Jason E. Butler and Roger T. Bonnecaze, Chemical
Engineering Science, Vol. 55, 1193-1204 (2000).
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Shear-induced particle migration for oscillatory flow of a
suspension within a tube,'' J.E. Butler, P.D. Majors, and R.T.
Bonnecaze, Physics of Fluids, Vol. 11, 2865-2877 (1999).
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“Imaging of particle shear migration using electrical impedance
tomography”, Jason E. Butler and Roger T. Bonnecaze, Physics of
Fluids, Vol. 11, 1982-1994 (1999).
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