Rob
Ansys Employee

I think the finer mesh is picking up some transient eddy shedding on the building. Can you plot contours of pressure on the sides of the building and take an image every 10 iterations for a few hundred iterations?  I'd use the execute commands feature to do this: doing it manually will be tedious! 


For a built environment model I usually reckon on a high imbalance due to these effects, and switching to transient isn't practical.