Velocity Verlet algorithm for dissipative-particle-dynamics-based models of suspensions

A velocity Verlet algorithm for velocity dependent forces is described for modeling a suspension of rigid body inclusions. The rigid body motion is determined from the quaternion-based scheme of Omelyan [Comput. Phys. 12, 97 (1998)]. An iterative method to determine angular velocity in a self-consistent fashion for this quaternion-based algorithm is presented. This method is tested for the case of liquid water. We also describe a method for evaluating the stress tensor for a system of rigid bodies that is consistent with the velocity Verlet alogorithm. Results are compared to the constraint-based rattle algorithm of Anderson [J. Comput. Phys. 52, 24 (1993)].