[Phantom]

theoretically the air would continue to swirl. u can test this by using the simple thing of having a bottle like a 591ml pop bottle, half full, swirling the liquid inside will make it funnel like a tornado. Now if you stop swirling the liquid will gradually stop. But if momentum is continued so will the swirl, so as long as air continues to blow past this thing it should continue to keep everything swirling. That said this one actually looks pretty restrictive. Very narrow openings on the other side. Whether you'd see any benefit is highly doubtful.