# Aerodynamics Question: Inner Channels and Vents



## gor (Nov 25, 2009)

simple question - vents of inner channels and wheel niches (pict) 
(dp1; dp1/e) http://www.dpcars.net/
http://www.dpcars.net/dp1dsn/index.htm (initial design stage )
purpose of placing it in certain areas how they affect aerodynamics?


----------



## Bowser330 (Jun 15, 2008)

I always thought those vents were there to draw the air out of the wheel well to provide ventilation for the brakes and tires because in racing both get very hot and when hot vary the performance level they provide...

The rear intake channels although are often used for mid-engine cars for both cooling via radiators and for air intake systems....Reference: Porsche turbo and Ferrari 360/430


----------



## gor (Nov 25, 2009)

Bowser330 said:


> I always thought those vents were there to draw the air out of the wheel well to provide ventilation for the brakes and tires because in racing both get very hot and when hot vary the performance level they provide...
> 
> The rear intake channels although are often used for mid-engine cars for both cooling via radiators and for air intake systems....Reference: Porsche turbo and Ferrari 360/430


may be tires (breaks - in the center to reduce unsuspended weight and polar moment)
they could channel air flow inside body, instead they let it out through vents ... and why in such places?...
may be main concern wasn't drag but downforce?


----------



## DavidDymaxion (Dec 1, 2008)

The shark gills on earlier Corvettes were found to significantly reduce front end lift.


----------



## dpcars (Dec 27, 2009)

the vents on top of wheel arches serve to relieve low pressure above the arch and therefore reduce lift. they are generally quite effective at that but do carry a drag penalty. on LMP cars you'll often see different vent configurations at different tracks as the teams trade off downforce and drag.

the vents behind the front wheels serve to let out the high pressure air that collects there, they don't do a whole lot when there are vents on top also (unless there is a front diffuser in which case diffuser outlet is generally behind the front wheels). the ones in front of rear wheels are mostly cosmetic on my cars although the general thought is to redirect air from the sides to the back and fill the wake somewhat. no idea whether it does anything useful (might be just generating drag). on other cars it is common to use that location for engine air, cooling air or rear brake duct intakes.

all this only applies to actual race cars. on street cars, overwhelmingly the ducts and vents are purely cosmetic and many are not even real vents but just solid plastic covers.

those interested in race car aerodynamics should check out www.mulsannescorner.com - it's a great source of info and pictures on what's being done and some good speculation on why. keep in mind that aero is not entirely the hard science that some think it is but has quite a bit of a black art to it - even the F1 teams are mostly guessing, they just have much better tools (and budgets) to evaluate whether their guesses work or not. this is because unlike airplanes (which work with mostly laminar flow in free air) cars have to deal with almost exclusively turbulent flow in proximity to ground, sometimes in the wake of other cars, and frequently with a crosswind component. it's a hugely more complex problem than an airplane.

dp


----------



## gor (Nov 25, 2009)

thank you, DP (who knows better "why?" - than author himself? : )))

thank you 4 the link - great source (btw. your site (dpcars.net) - is a very good source too : )))


----------



## automd (Feb 5, 2010)

DavidDymaxion said:


> The shark gills on earlier Corvettes were found to significantly reduce front end lift.


You bet man! Plus, it's one of the aerodynamic styling that influenced future _Corvette_ designs.


----------



## sunworksco (Sep 8, 2008)

gor said:


> simple question - vents of inner channels and wheel niches (pict)
> (dp1; dp1/e) http://www.dpcars.net/
> http://www.dpcars.net/dp1dsn/index.htm (initial design stage )
> purpose of placing it in certain areas how they affect aerodynamics?


Hello DP!
I'm planning on using DPCars suspension for my reverse-trike.
DP Cars is planning to make Ducati 1098 center-lock hubs for his uprights.
You can then use stock Ducati wheels or BST carbon fiber wheels.
John


----------

