Numerical simulation for polymer solutions based on a hybrid computation of multi-particle collision dynamics and coarse-grained molecular dynamics

Abstract

Numerical simulation of the flow-induced structure of complex fluids is an important issue in the flow analysis of complex fluids. Several schemes have been proposed for coupling the macro flow computation and the micro simulation of the inner structure of complex fluids. The present study proposed a numerical model based on a hybrid computation of multi particle collision dynamics (MPCD) and coarse-grained molecular dynamics (MD). The present model can easily treat hydrodynamic interactions among polymers, which play an important role in the dynamics of polymers in non-dilute solutions. In the MPCD, a solvent is represented by point-like particles (solvent particles) that move with a continuous distribution of velocities. The MPCD algorithm consists of a streaming step and a collision step. A scheme based on the MPC-AT+a algorithm for the collision step was adopted in the present simulation. Furthermore polymers were modeled by elastic dumbbells. The movement of beads of the dumbbells was computed using a coarse-grained MD, and the interaction among beads and solvent particles were considered in the collision step. Numerical simulations of shear flows were performed to analyze the dynamics of linear polymers. The numerical results agree well with both experimental results and predictions by other numerical methods.