Rob
Ansys Employee

Please can you post some images of the set up? A velocity inlet allows you to set swirl on the inlet. If you're using a tangential inlet then velocity normal to boundary is probably best. 


Back flow means you may need to move the outlet: otherwise press "help" on the pressure outlet panel & read up on radial pressure.   Also check the system centreline against the reference in the cell zone (default is for the axis to align to the z axis.