Mathematical-physical ways to express and address multiphase flow problems. This resource introduces the fundamental concepts that underlie the physics of multiphase flow and transport in porous media. It guides readers logically and step by step from simple concepts to advanced equations useful for addressing real-world problems including infiltration, groundwater contamination, and movement of non-aqueous phase liquids. The text develops governing equations for application to these and other problems in light of the physics that influence system behavior. Essentials of Multiphase Flow and Tr.