Note on Darcy's Law

Classical Darcy's Law expresses pressure gradient in a porous media as a linear function of the velocity difference between solid and fluid constituents. As such, this constitutive equation is frame dependent. The present article is an attempt to express this law in terms of frame independent quantities. The resulting expression shows that classical Darcy's Law may be justified on an approximate basis when the higher order quantities are neglected. (C) 2003 American Institute of Physics.