Brownian dynamics simulation of a multi-subunit deformable particle in simple shear flow

Abstract

The structure and dynamics of a multi-subunit deformable particle are investigated by Brownian dynamics simulations. Pairwise hydrodynamic interactions between spherical subunits are described by the Rotne–Prager diffusion tensor and non-hydrodynamic interactions by means of an attractive energy parameter, E. In the absence of shear flow, the average simulated particle structure ranges from ‘stringy’(E≲kT) to compact, with a transition region in between. Time-dependent numerical results are presented for the average subunit coordination number and the average particle perimeter area as a function of increasing shear rate. Particle elongation in the flow field leads to a reduction in the effective fractal dimension of the particle. The greatest sensitivity to shear rate occurs in the stringy–compact transition regime. Substantially different dynamic behaviour is obtained when the simulation is repeated without the inclusion of hydrodynamic interactions.