Regensburg 2010 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 35: Posters: Statistical Physics, Evolution, and Networks

BP 35.1: Poster

Donnerstag, 25. März 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).