About air dams, splitters, air curtains and diffusers

[Artemis]

"Form Follows Function". About air dams, splitters, air curtains and diffusers: functional, aesthetics or both ?

Interesting read: "Modifying Under-Car Airflow - A two-part series where we make significant undercar aero modifications" by Julian Edgar:
http://www.autospeed.com/cms/A_2455/article.html (part 1 of 2)
http://autospeed.com/cms/A_2456/article.html (part 2 of 2)

Findings by that author (non-BMW related):





Generally:




Mercedes-Benz SLR McLaren underbody:



Ferrari F430 diffuser:


Ferrari Enzo underbody:


Revozport 1M diffuser:



BimmerFile reporting in December 2010 on the 1M air curtains:
"There were a couple of surprises earlier this week when BMW took the wraps off of the 1M. Two of them lie squarely in the air intake area. First the bad. No there are no functioning brake ducts. Instead M has routed the normal intake areas into two radiators to help cool the twin turbo inline six. Unquestionably this is a disappointing move but according to sources a necessary one given the engine’s need for cooling. However the same sources are also telling us that the extra intakes weren’t as necessary as they could have been given the brakes propensity to cool on their own given the design of the system and wheels.
The internally-vented, cross-drilled cast iron discs measure 14.2 inches (360mm) in diameter at the front and 13.8 inches (350mm) in the rear. In addition each disc is connected to a floating aluminum hub by cast-in stainless-steel pins which further helps to reduce thermal loads.
Now the good. Somewhat surprisingly BMW is debuting it’s Air Curtain technology with the low volume 1M. We would have expected this to M to debut something like this on a higher volume car such as the M3 or even the M5. But instead M has used that technology to help define the look of the car with aggressive vertical slits just before each front wheel.
The air curtains improve air flow around the wheel arches with the benefit of significantly reduced turbulence. This feature consists of openings in the outer section of the lower front fascia that route high-pressure air through ducts at each front corner. The ducts are approximately 10 x 3 centimeters wide and are designed to channel air to openings at the front of each wheel arch, where it is discharged through a very narrow opening at high speed. The escaping air stream covers the side of the front wheels like a curtain, thereby reducing aerodynamically unfavorable turbulence around the rotating wheels.
Sources are telling us that this feature will play a key role in the development of future aerodynamic features on all BMWs. And of course this has all been possible with BMW’s new Environmental Testing Center."
(http://www.bimmerfile.com/2010/12/13...ain-in-detail/)




So, this brings us to the question whether a diffuser for the 1M (for example the Revozport one) is functional, aesthetics or both ?

[Pig Farmer]

Interesting read.