Nihon Kikai Gakkai ronbunshu (Sep 2019)
Application of the Brownian dynamics method to magnetic cube-like particle suspensions
Abstract
In the present study, we propose a new repulsive layer model in order to establish Brownian dynamics simulations for cube-like particles, although various repulsive layer models have been proposed by other researchers. In order to verify the validity of Brownian dynamics simulations with this repulsive interaction model, we address a suspension composed cubic hematite particles in an equilibrium situation. The results obtained here are summarized in the following. In the case of the ordinary model by Donaldson et al., the accuracy and the CPU time of simulations are significantly dependent on the number Nsph of spherical particles filling up one side of cube-like particle. As the value of Nsph is increased, the simulation time becomes more prohibitive although we can expect to obtain more accurate results. From the comparison in respect to the results of the orientational correlation function, we understood that the model with Nsph=3 exhibits quite different results in comparison with Monte Carlo results. This is because the corners and sides of the cubic particles cannot be modeled with sufficient accuracy in the case of Nsph=3. On the other hand, the model with larger values of Nsph tends to give rise to better agreement with Monte Carlo results. We may therefore conclude that the model of Nsph=5 or Nsph=7 should be used in order to obtain simulation results with sufficient accuracy if using their repulsive moled. In the case of our model, the simulation time corresponds to their model of Nsph=3, and the accuracy of simulation results is very similar to that for the models of Nsph=5 and Nsph=7. If considering the simulation time and the accuracy of the simulation results, we may conclude that our model has more significant advantage to the ordinary models in simulations for a suspension of magnetic cube-like particles.
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