Seminar Announcement, 03/31/2015
Levich Institute Seminar Announcement, 03/31/2015
Tuesday, 03/31/2015
2:00 PM
Steinman Hall, Room #312
(Chemical Engineering Conference Room)

Dr. Kyongmin Yeo
IBM T.J. Watson Research Center

"Phase Dynamics of Non-Brownian Suspensions"

ABSTRACT


Colloidal suspensions exhibit fascinating phase behaviors due to the subtle balance between hydrodynamic and Brownian di.usion at low shear rate. While the phase transitions in the equilibrium / near-equilibrium suspensions have been studied extensively, not much is known for the phase dynamics of particle suspensions in the hydrodynamic limit. In this talk, I will review some of our recent .ndings on the phase transitions of non-Brownian suspensions. The phase dynamics are studied by using a multiscale force-coupling method, which can simultaneously account for both near-.eld lubrication and far-.eld multi-body hydrodynamic interactions. When a basic inhomogeneity is introduced into the system by con.ning walls, the suspensions undergo interesting phase transitions, which depends on the volume fraction, distance from the wall and size of the gap. Due to the phase transitions, suspensions of sedimenting particles exhibit hysteresis and bifurcation. It is shown that the phase dynamics of the con.ned, non-Brownian suspensions can be manipulated by applying external couple on the suspended particles, which alters the bulk mechanical properties of the mixture. Finally, collective dynamics of active suspensions is studied in the monolayer, bi-disperse suspensions of spherical rotors. At low volume fractions, the opposite-spin rotors tend to stay together, which changes to phase separated uid at high volume fractions. Eventually, above a critical volume fraction, crystal structures of random spin distribution emerge, which is accompanied by a sharp drop in the energy conversion rate from the rotational to the translational kinetic energies.

BRIEF ACADEMIC/EMPLOYMENT HISTORY

2011, Ph.D. in Applied Mathematics from Brown University
2011 ~ 2012: Post-doctoral researcher at Lawrence Berkeley National Lab.
2013 ~ 2014: Post-doctoral researcher at IBM TJ Watson Research Center
2014 ~ Present: Research Scientist at IBM TJ Watson Research Center

RECENT RESEARCH INTERESTS

Microhydrodynamics, active suspensions, multiscale physics modeling, uncertainty quantification, high performance computing



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