ABSTRACT
Some new megascopic variables which appear in porous media theories are saturation, porosity, megascopic concentration and megascopic capillary pressure. Here saturation is the megascopic volume fraction of a phase which is macroscopically segregated. Porosity is the volume fraction of space which is void of solid. Concentration will simply be defined as the mass fraction of a particular phase per unit volume; thus megascopically it will be a composite of pore scale concentration and megascopic saturation information. Capillary pressure will refer to the pressure difference across fluid interfaces at the pore scale. Megascopic capillary pressure will refer to the average pressure difference between fluids at a scale orders of magnitude larger than the pore scale.
