Atomistic, mesoscopic and continuum hydrodynamics: coupling liquid models with different resolution

Friday, November 7, 2008 - 10:30am - 11:15am
EE/CS 3-180
Rafael Delgado-Buscalioni (Autonomous University of Madrid)
The final goal of multiscale methods based on domain decomposition, is
to retain full atomistic
detail only where needed (within a region of interest), while using
a coarse-grained model to introduce the essential information about the
surroundings dynamics. Importantly, the atomistic region becomes an open
which exchanges mass, momentum and energy with the exterior. The
hydrodynamics of flux exchange can be
solved using an hybrid molecular-continuum description (hybrid MD)
[1,2]. However, molecule exchange across the hybrid interface becomes
a complicated task as one deals with more complicated molecules,
essentially owing to larger steric hindrance. A way to solve this
bottleneck is to combine hybrid MD with adaptive coarse-graining. The
set-up is like the layers of an onion [3]: the atomistic model lies at
the core, surrounded by a thermodynamically compatible coarse-grained
model, which interfaces with a continuum description of the liquid
(maybe also including hydrodynamic fluctuations). Finally, open
boundary conditions for the continuum description [4] allow evacuation
of (shear, heat or sound) waves out of the whole system, and let it
behave in a grand-canonical way, in contact with the prescribed
outer thermodynamic state.

[1] G. De Fabritiis, R. Delgado-Buscalioni and P. Coveney, Phys. Rev.
Lett.97, 134501 (2006)

[2] R .Delgado-Buscalioni and G. De Fabritiis, Phys. Rev. E 76, 036709

[3] R. Delgado-Buscalioni, K. Kremer and M. Praprotnik, J. Chem. Phys.
128, 114110 (2008)

[4] R. Delgado-Buscalioni, A. Dejoan, Phys. Rev. E, in press, (2008)

MSC Code: