I have a made model to recirculate air, I first started with no ducting, just a pressure outlet at the end to see if the air velocity was what I wanted (green). I have added ducting to simulate re-circulation of the air and I now keep getting the error message 'A vortex crosses the pressure opening'. To make the air circulate I used one (1) face of a lid as the inlet and the opposite face as the outlet. I think this is where the problem is coming from, but everything still looks nice.

Is this a problem? How can I explain this to my colleagues if it isn't a problem? An explanation is warranted as it does say 'warning'. Please see the attached images for a better understanding of my model and error messages. The mean air velocity through the room is roughly 0.15 m/s.