Quote:
Originally Posted by dennyt
I'm surprised by this image. Diffusers won't help station wagons?
 |
I believe the answer is in the following diagrams:
It's all about eddies. In all cars there are eddies behind the rear wheels, but in a sloped-back car there also counter-rotating eddies from the rear pillars. The two (partially) cancel out - by increasing the diffuser angle (up to a point) the lower eddies are increased in size to be a better match for the upper eddies (allowing better cancellation). See figures
Ba and
E in the second diagram.
In a square-backed vehicle there are no upper eddies, only lower. By increasing the diffuser angle these are increased in size, but do not cancel with anything. Figure
C in second diagram.
Looking at figure
D makes me wonder about adding vertical fins to the sides of a square-back's diffuser. On the other hand, adding a Kammback would probably be a better idea.
__________________
e·co·mod·ding: the art of turning vehicles into what they should be
What matters is
where you're going, not
how fast.
"... we humans tend to screw up everything that's good enough as it is...or everything that we're attracted to, we love to go and defile it." - Chris Cornell
[Old] Piwoslaw's Peugeot 307sw modding thread