  The fluid flow through porous media is described by Darcy's law, while the
fluid/wall interactions can be neglected. In nanopores, where adsorption
dominates, Darcy's extension has been made, but approaches able to describe
flows in mesopores are still lacking. We show here that molecular flows through
nano-constrictions is well described by Berverloo's law, predicting the mass
flow rate of granular material through macro-apertures. This molecular and
granular analogy, allows to derive a relationship providing a theoretical
framework for the molecular flow in disordered mesoporous systems.
