Formula behind the darcy
 

Hi guys

I'm at a degree work in a ingeneer's school.

My work based on the topic "airflow through a porous zone".

I am working with porousSimplefoam and put there the darcy number in. But actually I cannot comprehend which formula is behind the darcy number.

Can you explain that?

Thanks for the help,

hunzs2

http://www.google.de/search?q=darcy+number+cfd
http://en.wikipedia.org/wiki/Darcy_number