2d geometry or 3d for porous media?
 

Hi to all,I have a porous media in a tube with 4cm lenght and 5cm diameter in my prblem,I want to know which of 2d geometry or 3d has more accurate results in fluent?

I run my problem in 2d in the most simple state of it in fluent,but the results were very irrelevant!
For example velocity was the same inlet velocity in the whole of my system!
Is it because of 2d geometry?