Topological and Geometrical Random Walks on Bidisperse Random Sphere Packings

Motivated by a problem arising from pharmaceutical science [B. Baeumer et al., Discr. Contin. Dyn. Sys. B 12], we study random walks on the contact graph of a bidisperse random sphere packing. For a random walk on the unweighted graph that terminates in a specified target set, we compare the number of steps and the total euclidean length of the walk. We find a linear relationship between the two metrics with a proportionality constant that can be calculated from the edge length probabilities of the contact graph.