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Piwoslaw · 03-26-2010, 04:10 PM

I found this in Piechna's book. It's based on Kohri and Numata's paper[1].

As can be seen, a diffuser hurts aerodynamic drag in vehicles with a square rear (vans, station wagons). It's something about the diffuser causing eddies that cancel with countereddies from the sloped rear end. In the square rear there are no countereddies, so there is no cancellation.

[1] Kohri I., Numata N., Effects of rear end configuration of vehicles on aerodynamic drag, JSAE Review, December 1985.

03-26-2010, 04:10 PM	#25 (permalink)
Piwoslaw aero guerrilla Join Date: Oct 2008 Location: Warsaw, Poland Posts: 3,750 Svietlana II - '13 Peugeot 308SW e-HDI 6sp 90 day: 58.1 mpg (US) Thanks: 1,333 Thanked 749 Times in 476 Posts	I found this in Piechna's book. It's based on Kohri and Numata's paper[1]. As can be seen, a diffuser hurts aerodynamic drag in vehicles with a square rear (vans, station wagons). It's something about the diffuser causing eddies that cancel with countereddies from the sloped rear end. In the square rear there are no countereddies, so there is no cancellation. [1] Kohri I., Numata N., Effects of rear end configuration of vehicles on aerodynamic drag, JSAE Review, December 1985. Attached Thumbnails __________________ 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 Last edited by Piwoslaw; 03-26-2010 at 04:44 PM..