I use Ansys Fluent on Linux for CFD. Unfortunately it is not open-source - it is actually the only closed source program on my Gentoo laptop. Being a student and taking a class (in turbomachinery) with a company started by the same mentor as them, I get it for free, though. If you can get it through connections of a student or someone in industry they want to entice into site licenses, I highly suggest you do.
A good open-source CFD solver is
OpenFoam. Unfortunately it may be a bit challenging to use if you are not familiar with the field.