Something I notice, the air on the side is moving Up...I'd think we'd wanna do what ever it takes to keep the air moving in a straight line in relation to where it starts. If this is achieved then the air will end up where it started before going around the shape and this will accomplish the best result. If the air is moving up, then it will meet the air coming from the top and create the swirl (AKA Vortex). I don't know what it will take to balance this out.
ERTW, This is GREAT stuff you are putting up here, I don't know what we did to deserve you but I feel lucky to have you around. A Huge
THANKS from me!