Relative permeability

Relative permeability is a measure of a porous material's ability to transmit fluids compared to a reference fluid, typically water or air. It quantifies the ease with which different fluids can move through a porous medium, such as soil, rock, or a filter cake, under conditions of partial saturation with multiple fluid phases. In the context of multiphase flow, relative permeability is defined for each phase (e.g.