(79g) Modeling of Nanoparticle Motion in an Incompressible Newtonian Fluid: A Comparison Between Fluctuating Hydrodynamics and Generalized Langevin Approaches

In order to obtain an accurate
description of nanocarrier dynamics in the
bloodstream and near wall interactions, we have developed a
formalism where both the Brownian motion as well as the hydrodynamic
interactions are important. We employ a direct numerical simulation adopting an
arbitrary Lagrangian-Eulerian based finite element
method to simulate the Brownian motion of nanocarrier
in an incompressible Newtonian fluid. Thermal fluctuations are implemented
using three different approaches: (1) fluctuating hydrodynamics approach; (2)
generalized Langevin approach; (3) a hybrid approach
combining (1) and (2) to incorporate memory effects. At thermal equilibrium,
the numerical predictions for temperature of the nanoparticle, velocity
distribution of the particle, decay of the velocity autocorrelation function,
diffusivity of the particle and particle-wall interactions in the presence and
absence of adhesive interactions are computed for various flow conditions. We
show that the hybrid approach simultaneously preserves the canonical
distribution as well as the hydrodynamic correlations.

References:

1.    Nanoparticle Brownian motion
and hydrodynamic interactions in the presence of flow fields, B. Uma, T. N. Swaminathan, R. Radhakrishnan, D. M. Eckmann,
P. S. Ayyaswamy, Physics of Fluids, 2011, 23,
073602. DOI: 10.1063/1.3611026.

2.  Generalized Langevin
dynamics of a nanoparticle using a finite element approach: Thermostating
with correlated noise, B. Uma, T. N. Swaminathan, P.
S. Ayyaswamy, D. M. Eckmann,
R. Radhakrishnan, J. Chem. Phys., 2011, 135, 114104. DOI:
10.1063/1.3635776; Erratum, 136, 019901, 2012.

3.    A hybrid formalism combining
fluctuating hydrodynamics and generalized Langevin
dynamics for the simulation of nanoparticle thermal motion in an incompressible
fluid medium, B. Uma, D. M. Eckmann, P. S. Ayyaswamy, R. Radhakrishnan, Molecular Physics,
2012, in press. (DOI: 10.1080/00268976.2012.663510)

4.  Hybrid scheme combining fluctuating
hydrodynamics and generalized Langevin dynamics for
nearly neutrally buoyant particle in stationary medium, B. Uma, D. M. Eckmann, R. Radhakrishnan, P. S. Ayyaswamy,
ASME Journal of Heat Transfer, 2012, in press.