I've been thinking about prototyping the boattail (it's literally a matter of time) and would like to bounce some ideas off those of you who actually studied aerodynamics or dropped cash for the Hucho book.
The liftback Probe has attached flow across the rear window and a typically boxy bottom end. It would probably be best described as Ba on the chart.
Illustrated are two vortexes forming on the C Pillars and rolling inward toward the center line. Even considering the attached flow, these should exist because of the pressure differential.
Since I plan on extending the rear end two feet or so at a 15* angle top and sides (and verifing it with tuft testing), there may be a unique opportunity. I seem to recall reading somewhere that two counter rotating vortexes on each side could neutralize each other. Piwoslaw posted something about counter rotating "eddies" but I'm not sure if that would technically be the same thing.
http://ecomodder.com/forum/167791-post25.html
That graph and explanation suggests that a rear belly pan angled 15 degrees upward from horizontal would in effect cancel out the eddies coming off the liftback form.
If that is true, is there anything else I could do or should think about in shaping the boattail to help neutralize this pressure differential without making it worse? Anything to look out for?
Thank you all very much.
