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2. Generating MultiDirectional Pore-Network (MDPN)
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Figure 2.4: Example of eliminated sites, isolated clusters, and deadend
bonds.
or we can keep them as the dead-end pores of porous media.
Finding and eliminating isolated clusters is not as easy as in the case of deadend
sites. To do so, we employ a search algorithm to find the “backbone”. We
start from one of the boundaries across which flow is allowed. For each and
every site on that boundary, we apply a search algorithm to find all the sites
connected to it directly or through other sites. At the end, if we reach the
other flow boundary, it means that this group of sites forms a backbone. After
finding the backbone, we eliminate all other bonds as they belong to isolated
clusters. To do tracking, it is crucial to have an efficient search algorithm. We
have employed a algorithm based on the frequency of bonds. The details of our
algorithm are given in Appendix A. Looking at the topology of the resulting
network, our network is of semi-regular type since, after the elimination process,
we do not always have a site at each lattice point. In fact, lattice points do
not even need to be exactly in regular cubic pattern, and we have freedom to
shift them away from the lattice point and/or move them into the position of
eliminated pores or clusters, given that they would not have any contact with
any other neighboring site (Figure 2.5). This feature along with different pore
body sizes (thus, different bond lengths) makes this network a semi-irregular
type. However, since such a network is a subset of a regular network (e.g., the
cubic lattice network), sites are only connected to their nearest neighbors and
the network contains no long bonds. Arns et al. [2004] considered the effect of
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