I am trying to see what temperature a semiconductor reaches inside of a burn-in socket. I have downward air impinging on a finned heat sink atop a burn-in socket inside which a semiconductor is generating heat. I also have horizontal air travelling in a direction that is transverse to the fins and exits through a pressure opening at atmospheric pressure. I have a persistent "vortex crosses pressure opening" warning. I have tried enlarging the domain so that the vortex moves/disappears but have had no change in the temperature plot. I have seen this warning in past simulations, but have not seen this type of curve behavior. What could be responsible for this and how can I fix it to get a smoother temperature plot?