Momentum balance and motion equation

Abstract

This chapter is devoted to the macroscopic fluid motion equation, emphasizing its origin as a momentum balance equation. Starting point with the momentum balance equation of a phase, and introducing certain simplifying assumptions, this equation is reduced to the well-known (linear) Darcy’s law. Other non-Darcian forms of the motion equation—Forchheimer, Kozeny and Klinkenberg- are also presented.