Quote:
Originally Posted by ChazInMT
You need to carefully consider how fast the air is being asked to close in behind the shape, if it is too fast, it creates low pressure. If this low pressure is in close proximity to an area of high pressure, the air will move up from the high to the low and if strong enough a difference, will set a vortex in motion which will be a real drag.
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This is how my roof wing (see link in signature) works.
I had not really considered that if drawing too much air downward via pressure differences that a large drag causing vortex could be formed.
To tell the truth, it is difficult to see large trailing vortexes in wind tunnel smoke streams.
And CFD models mostly look like irrelevant swirls of psychedelic colors to me.
The CFD models based on pressure (verses flow) are even more ambiguous to my eyes.
Essentially everything aft of the car just looks like a mess to me, but I am slowly learning the differences.