Quote:
Originally Posted by Thenorm
i've always wondered about modern sedans. the rear glass transition always seems smooth enough. that I bet the air stays attached, even though its sub template and producing a low pressure zone (acting like an airfoil)
And as long as you have a horizontal or convex surface at the end to turn the air flow again and produce a high pressure zone, it might work better than a kamm back.
case in point is the new mercedes CLA which gets an absurdly low Cd and even the prius which is sub-template
So for your car, maybe all you have to do is extend the horizontal of the trunk out closer to template
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*Hucho tells us that on 'fast' rooflines,that there will be a strong downwash in the center,holding the air attached,and the counter-rotating longitudinal vortices washing the C-pillar area will tend to reinforce the downwash.
*The attached vortices themselves are high drag and cut into the benefit of the center downwash,increasing the overall drag compared to a pure fastback.
*Hucho's experience is that nothing will produce lower drag than a proper fastback.They have no separation and they have no vorticity.
*It's possible that the cars notchback has already been optimized.This body type has the most complex flow,and rear flanks,C-pillars,backlight,and roof must be 'tuned' to one another.Hard to do without a full-scale wind tunnel.