Regensburg 2010 – scientific programme
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BP: Fachverband Biologische Physik
BP 35: Posters: Statistical Physics, Evolution, and Networks
BP 35.1: Poster
Thursday, March 25, 2010, 17:15–20:00, Poster B2
Semiflexible polymers under the influence of a pressure driven Poiseuille flow — •Sebastian Reddig and Holger Stark — Institut für Theoretische Physik, TU-Berlin
We introduce two different models for a semiflexible polymer under the
influence of a pressure driven Poiseuille flow between two planar walls.
In the first model we describe the polymer as a bead-spring model and
use a discretized representation of the wormlike chain model for its
bending elasticity. We neglect hydrodynamic interactions with the
bounding walls but investigate the influence of the non-zero bead size
which disturbes the external flow field. We explicitly calculate this
disturbance from a series expansion following J.K.G. Dhont1.
It leads to additional terms in the equations of motion that cause
cross-streamline migration in the Stokesian dynamics of the polymer.
The direction of this migration can be controlled by varying the bead
sizes.
In the second model we approximate the beads by point particles and
describe their hydrodynamic interactions with the two-wall Green tensor,
derived by R.B. Jones2, taking into account the no-slip condition
at the bounding walls.
Because the evaluation of the two-wall Green tensor consumes much
computer time, we describe the polymer in this model by a simple dumbbell.
Using Brownian dynamics simulations, we measure the center-of-mass
probability density of the dumbbell and compare the results with
theoretical predictions.
1An Introduction to Dynamics of Colloids,
Elsevier, (1996).
2Spherical particle in Poiseuille flow between
planar walls, J. Chem. Phys, 121, 483 (2004).