Quote:
Originally Posted by MetroMPG
Interesting!
I know you haven't forgotten you're viewing in 2D, and focusing on the roof/decklid flow.
While the wake cross section may be bigger at the end of the Kamm'ed car, would the Kammback shape reduce the likelihood/magnitude of the pair of drag inducing trailing vortices - more probable on a sedan/notchback?
Also, that entrained separation bubble at the base of the sedan's rear window takes fuel to feed (believe I read Phil making a comment to that effect, anyway).
There's a reason the Prius, Volt, Insight 1&2, A2, and so many others are hatchback/Kammbacks!
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So yes, I've diverted some of my computing power to a better model rather than CFD.... Because I need more than a cut plot to make more valid conclusions.... I am now 95% near a suitable 3D model - it just needs some clean up in a few areas... Those square chunks aren't really there, it's my video card not up to the task of rendering such a large and complex model.
On the subject of the Prius et. al....
The Prius is a rather large car - at least, about the same as my Jetta... The termination of my Kamm (top trailing edge) is much higher than the Prius' termination. I think that will have a significant effect on overall aero performance.
That gives me a good idea though... I need to find either a model of the Prius, or a good side photo in which I can parametrize the shape.... Then we'll see if I can move that over to my model - I'm holding a trace of my car's profile against the Prius - the rear end is
very close (which is exciting for me).