Liquid dynamics in a crowded environment: Bond percolation vs site percolation.

Abstract

The main problem studied is how the diffusion of liquid occurs in the presence of obstacles. In general, this question cannot be reduced to either bond or site percolation, because in real media, the diffusion problem is a complex combination of bond and site percolation. In this work, we make a comparison between site and bond percolation, where the motion of the elements is closely correlated, which is made possible by the unique properties of the dynamic lattice liquid algorithm (no other method allows this). It is clear that even at the two extremes, it is impossible to reduce the problem to just one type of percolation. It should be emphasized that the above comparison has been made within the framework of a single model, which seems very difficult to do with other methods. Extensive and systematic computer simulations have been carried out on a dense (completely filled system) athermal two-dimensional liquid model on a triangular lattice. The behavior of all investigated parameters clearly shows that, for the same obstacle concentration, the liquid molecules in the model with blocked sites are much more mobile, especially as the probability of blocking or the obstacle concentration increases. The research presented here shows that the dynamics of the system is closely related to the morphology of the system. What matters is not only the absolute number of obstacles but the detailed morphology of the local distribution of obstacles and bonds (channels) of the systems.