more finds from an image search for hierarchy and scale “An example of hierarchy of scales associated with one-phase flow in vuggy rocks” “In this paper, the macroscopic representation of one-phase incompressible flow in fractured and cavity (or vuggy) porous media is studied from theoretical and numerical points of view. A single-domain (or equivalently a Darcy-Brinkman) type of approach is followed to describe the momentum transport at Darcy scale where the fracture or cavity region…” ooh computational geoscience https://www.researchgate.net/publication/267574159_Investigation_of_the_effective_permeability_of_vuggy_or_fractured_porous_media_from_a_Darcy-Brinkman_approach