Porus media simulation - flow direction

ayapan

Hi friends,

I need a help in suimulating porus media (filter)in cfx. I have created a subdomain in my fluid volume and specifying a source for the subdomain.

The filter which am using is a cylinderical one flow entering along the longitudinal direction and leaving from the radial surface. (approximately at mid of the filter gerometry)

My question is how to specify the flow direction in cfx and which co-ordinate i should use??? cartesion co-ordinates or cylinderical co-ordinates.

reg Ayapan