Continuum-microscopic computational modeling of non-equilibrium<br/><br/>viscoelastic flow

Wednesday, October 14, 2009 - 3:30pm - 4:10pm
EE/CS 3-180
Sorin Mitran (University of North Carolina, Chapel Hill)
The problem of coupling microscopic and continuum-level descriptions of
complex fluids
when the microscopic system exhibits slow relaxation times is
considered. This type of
problem arises whenever the fluid exhibits significant memory effects.
The main difficulty
in this type of multiscale computation is the initialization of
microscopic configurations and
establishing the duration of microscopic evolution that has to be
computed before a continuum
time step can be taken. Density estimation theory is applied to
determine the distribution
of random variables characterizing the microscopic system. Additional
mesoscale equations
for the probability density functions required to characterize
microscopic states are determined
from successive bursts of microscopic simulation. The time evolution of
the mesoscale equations
is computed using high-order Adams-Bashforth-Moulton predictor-corrector
algorithms. The
overall computational model is exemplified on a Rolie-Poly fluid. The
main benefit of the approach
considered here is that the complication of deriving an algorithm for
complicated constitutive laws
is sidestepped without the need for prohibitively expensive computation
at the microscale.
MSC Code: