Dear Mr. or Mrs:

Can you tell me how to set a_ij for monmentum equation in pourous media? The pourous media is one ceramic plate in which there are thousands of parallel pores.

Thank you Sincerely yours, Harry

If you don't have pressure drop data, you can quickly estimate the permeability from the loss through each pore. The loss through each pore will be the same. Take each pore as a cylinder of some diameter and estimate the pressure drop. Compute permeability from Darcy's law.