Simulação de suspensão de bactérias utilizando dissipative particle dynamics

Abstract

The term active matter is used to designate systems wich are formed of (or have) agents with the capacity to convert stored or ambient energy into movement. These agents are able to cluster and produce emerging behavior, which manifest themselves as several different phase transitions in these systems. A suspension of bacteria can be considered as an active matter, which in addition to the transition between phases also has the ability to alter the rheological properties of the mixture. In this work, we evaluated dynamic phases and obtained rheological properties of suspensions of bacteria using the method Dissipative Particle Dynamics. The method DPD was used for being able to describe effects that occur only in the mesoscale. To do this, we modify the programs LAMMPS and DL_MESO to add the active particle model to the classical DPD method. The simulations carried out show that there are divergences between the phase diagram obtained by the two programs. We used the boundary conditions of Lees-Flwards, in order to model the shear effect in the simulation box of the DPD. In the case of a simple fluid, the deficiency of the DPD method is verified by increasing the shear velocity. We have thus verified that, in the case of bacterial suspensions, this deficiency persists, which impossibilitate a broad analysis of the effect of active particles on viscosity.