Aero.. wheel well vents

[zac510]

Seeing as we've been having some good ol discussions about aerodynamics lately I thought I'd post up this photograph from the Britcar pits last month.

It appears to be inspired by the F1 'chimneys' as it carries that general shape and profile. I wonder if it has ever been near a wind tunnel? The arch is also vented to the rear in addition to this chimney.

Might it be flawed if the transition from the wheel well to the chimney is not smooth and contoured?

What do you think?

[trikesrule]

What a load of crap......trikes

[rcarr]

From my understanding, it will be for releasing unwanted pressure (which creates drag) from inside the wheel well. That maybe his reckoning anyway but I reckon it would create more drag than having nothing there at all. The angle between the wheelarch and the vent is too great, almost 90 degrees so very little air will escape through that vent.

Its similar to what sportscars and DTMs cars have with vanes on their wheel arches.

Have a look at Peter's front wheelarch.
http://automobile.2405.com/automobil...a_DTM_2405.jpg

Much the same as this too:
http://www.davidanderson.org.uk/imag...rt/xjr10-e.JPG

[zac510]

Say what you think trikes

Yes I understand what it is trying to achieve but wonder about its efficiency without any internal ducting.

[meb]

...is this a vent or an aero device designed to work the air outside the fender well? I'm not an expert, by any stretch, but louvers wopuld seem to allow much more surface area and less drag...

I've thought about many aero things and louvers above the front fenders seem like a fairly decent idea...if not at the track, at least at a pub!

[GORDON STREETER]

Looks like somebody's been at Photoshop on the computer to me !

[austin_ob]

i cant see why they bothered with this as they could have just used gills on top of the wheel arch like you see on le mans cars.

[rcarr]

Maybe its a boy-racer wanting to make his car look like an F1 car!

I'd like to see him or a mechanic try to refuel it though, amateur mechanics are not always 100% accurate when it comes to refuelling in the high pressure pitstops of an endurance race.

[zac510]

Originally Posted by GORDON STREETER

Looks like somebody's been at Photoshop on the computer to me !

I will post another picture when I get home, otherwise one of the Britcar lads might come in here and back me up!

[meb]

No, no, no, we missed it! It's a fuel pod rest stand...in case the guy gets tired

[rcarr]

Maybe its a camera housing that did't get finished in time before the race?

[Cameron Winton]

I always thought venting wheel wells was all about reducing lift from the trapped circulation caused by circulation

I also thought chimneys worked by extraction - doesn't look terribly efficient

[rcarr]

Cameron Winton have you heard of lift induced drag? Thats my understanding anyway. One of my projects had the lift induced drag in a static windtunnel, it would have created lots of downforce if it had been in a moving ground.

[meb]

I believe the area inside the front fender is at higher pressure than the fender well...but relates to speed, shape etc. And all things in this world move from high to low pressure.

Interesting that in some 80s and 90s LeMans applications these vents were sealed off...but those same applications had larger splitters and larger rear wings moved farther off the rear deck - Mercedes/Sauber C9 for example.

[Locost47]

I've got to agree with Trikes - it just looks plan daft. Unless there are rules banning louvres or something I just can't see why you would ever opt for a chimney.

[AU N EGL]

Maybe it is a beer holder?

[zac510]

louvres are within the rules. The front guard of this car had the traditional louvres.

[Hitech]

I think that there is more to this than meets the eye. This looks like a vortex extractor device that sucks air out of the wheel arch as air travels over the top of the open pipe. The principal is well known and is used in laboratories to draw vacuum using devices clamped to running water taps. You can see the principal when you blow across the top of an open bottle, the air inside hums as it vibrates under slight vacuum, and it's used in chimney designs to extract fumes. I've always intended to try it on my single seater with a large open topped tube behind the roll bar extracting air from the undertray, but have never got round to it.

[zac510]

Yes I've often wondered how important those winglets that the team affix to the chimneys are to the air flow out of the chimney or whether it is just a convenient position for something further downstream. But it's a little beyond my knowledge.

[Locost47]

Originally Posted by Hitech

I think that there is more to this than meets the eye. This looks like a vortex extractor device that sucks air out of the wheel arch as air travels over the top of the open pipe. The principal is well known and is used in laboratories to draw vacuum using devices clamped to running water taps. You can see the principal when you blow across the top of an open bottle, the air inside hums as it vibrates under slight vacuum, and it's used in chimney designs to extract fumes. I've always intended to try it on my single seater with a large open topped tube behind the roll bar extracting air from the undertray, but have never got round to it.

This is true but the actual drop in static pressure due to this sort of device is only marginally greater than you get from a rearward-facing step like a louvre and yet you aren't extracting effectively from the target portion of the circumference of the wheel well. If they had several staggered smaller ones it would probably work better.