Foam Flow: Darcy vs NS Equation

[Talal]

According to the attached article, Foam is a Bingham plastic. Darcy's equation with Bingham's extension can be used to describe the flow. My question is, for foam flow, does utilising Darcy's equation a reasonable approach ? What benefits does it have, or better yet, why not use Navier stockes equation ? Also in the attached article foam is treated as a single phase.

 

[Chestermiller]

According to the attached article, Foam is a Bingham plastic. Darcy's equation with Bingham's extension can be used to describe the flow. My question is, for foam flow, does utilising Darcy's equation a reasonable approach ? What benefits does it have, or better yet, why not use Navier stockes equation ? Also in the attached article foam is treated as a single phase.

The Navier Stokes equations only apply to a Newtonian fluid. This fluid is non-Newtonian, so its pressure drop-flow rate behavior will be different. I have problems with this paper, particularly Eqns. 22 and 23, which are definitely incorrect.

 

[Talal]

Thank you very much for your answer.