Dirty air sensitivity and regulations

[rjsa]

Run a car without a front wing. Is parasitic drag increased, decreased, or unchanged?

It's increased, because instead of flowing over the relatively streamlined front wing, from which it would have been directed toward beneficial areas downstream and away from areas that might increase interference drag, it catches more of the decidedly un-streamlined front wheels and is allowed to flow unimpeded into areas around the sidepods that are often no more streamlined than a brick.

http://i.imgur.com/0DojFdV.jpg

I've clues to spare, ese.

You were saying that removing the front wing would increase drag. That's not downplaying 20% of the drag. It is saying it nets negative.

Now we're just entering the high school debate routine. I'm out.

[bhall II]

Now we're just entering the high school debate routine. I'm out.

I think you just can't ignore the voice of your inner pedant that has you convinced everything I say is exclusive to itself, and that sort of "gotcha" bullshit is the perfect embodiment of the "high school debate" dynamic you decry.

If you don't want to look for common ground, that's unequivocally your right. But, it has absolutely nothing to do with me or anything I've said.

You were saying that removing the front wing would increase drag.

Run a car without a front wing. Is parasitic drag increased, decreased, or unchanged?

[turbof1]

Bhall, I do have to state this was the initial comment from you:

Because the wing has no impact on frontal area, it doesn't contribute to form drag

I do not know if parasitic drag increases (because form drag is a part of it, but only a part). I do not believe however that the front wing does not contribute to form drag. In 2 dimensional space that might be true, but in 3 dimensional space surface is still increased by the front wing. Of course the form drag of the wing will decrease the form drag of the wheel because the partly covers it. but the wheel will still produce some form drag. I do not believe it's a zero operation.

[bhall II]

What I should have said, and what I've tried to clarify, is that the front wing doesn't add to the car's form drag, which is influenced by frontal area and by shape, or that it could conceivably be made worse without a front wing. The front wing's effect on the wheels, for instance, is clearly evident in the CFD images below...





...and has been experimentally investigated (the article is worth a read):

In 2007 Martinus van den Berg published a PhD thesis on the interaction between a rotating wheel and an inverted wing. The research was sponsored by the Honda F1 team, which has, of course, evolved into the Mercedes F1 team; the same team responsible for the 2012 front-wing F-duct.

The most interesting conclusion of van den Berg's research was that the front-wheel drag is greater at high front-wing ride-heights than it is at low ride-heights.

In its original context, the idea I intended to express (still) makes sense. But, that doesn't in any way mean it should be viewed as absolute.

It is my opinion that the comparably minor detrimental effects of a standard, passive wing don't justify the adoption of a fan wing concept that would increase weight and complexity. That's it. Any other implications are purely unintentional.

[rjsa]

What I should have said, and what I've tried to clarify, is that the front wing doesn't add to the car's form drag, which is influenced by frontal area and by shape, or that it could conceivably be made worse without a front wing. The front wing's effect on the wheels, for instance, is clearly evident in the CFD images below...

http://i.imgur.com/HB2lHnL.png

http://i.imgur.com/dF5bNgc.png

...and has been experimentally investigated (the article is worth a read):

In 2007 Martinus van den Berg published a PhD thesis on the interaction between a rotating wheel and an inverted wing. The research was sponsored by the Honda F1 team, which has, of course, evolved into the Mercedes F1 team; the same team responsible for the 2012 front-wing F-duct.

The most interesting conclusion of van den Berg's research was that the front-wheel drag is greater at high front-wing ride-heights than it is at low ride-heights.

In its original context, the idea I intended to express (still) makes sense. But, that doesn't in any way mean it should be viewed as absolute.

It is my opinion that the comparably minor detrimental effects of a standard, passive wing don't justify the adoption of a fan wing concept that would increase weight and complexity. That's it. Any other implications are purely unintentional.

That's what I call a scrapbook.

The images are not even related, the color scales are inverted. What you call "the effect of the wings on the wheels" is a huge red splotch, that if you check the scale on top of the images is a high pressure point, happening to have pressure even higher than the driver's forehead that's on free airflow.

The linked article goes on about endplates and wingtip vortexes never mentioning parasitic drag. It also mentions the caveat that study was made with the pre 2009 narrow wings which channelled air inside, not over and around the tyres.

It in no shape or form supports the theory that a wing does not add parasitic drag: the wing does add parasitic drag, It's seen as another body by the flow - the fact that it's connected by pillars to the car won't alter that.

So it's my opinion that this is a whole lot of unrelated googled pictures and text pasted up in a way to support the last understanding you have of the fluid dynamics phenomena surrounding a F1 car.

[bhall II]

You really ought to learn how to ask questions.

The effect of the front wing is evidenced in the areas on the wheels that are not red. (FYI: "Evidenced" doesn't mean "confirmed," and the images don't have to be related to illustrate the point I'm trying to convey.. So, please don't twist those things into something else, too.)





It's clear I've given you too much credit here. I won't make that mistake again, nor will I even bother to ask why you can't connect the dots from the McCabism article (or why you refuse to even try to discuss this in good faith).

Take care.

[turbof1]

People, please be a bit more respectful against one another. The atmosphere has become very grim in this topic at an alarming rate. Maybe it's best to step away for a few hours and try to put things in perspective afterwards.

[trinidefender]

Bhall is correct. The front wing can actually lower total drag around the front wheel through a few principles and methods.
1. Vorticity, a vortex that flows around the outside and above the front tyre generated by the front wing helps to negate some of the turbulent eddy flows around and behind the tyre. There are 3D models of a sauber car in CFD that show this. I'm sure Bhall has seen them and can post if he so desires, I neither have the time nor the energy right now evidenced by my lack of activity on this forum for the last few months.
2. The general upward and outward flow promoted by the front wing. This effect essentially "pushes" (for want of a better word) airflow around the tyre and reduces the size of the high pressure zone that the front of the tyre sees. Yes there is still a fairly large high pressure zone in the last picture however if you were to look at a CFD or windtunnel pressure model of a car with a tyre and no wing in front of it the high pressure zone would extend from the centre of the tyre vertically all the way down to the floor.
There are other ways but just these two principles are enough to demonstrate in a fairly simple way how drag is usually reduced on the wheel by the wing itself.

[turbof1]

I think that's the key here: without making a comment on the total drag footprint, the wing does reduce both induced and form drag on the wheel.

What you call "the effect of the wings on the wheels" is a huge red splotch, that if you check the scale on top of the images is a high pressure point, happening to have pressure even higher than the driver's forehead that's on free airflow.

I gave this some thought and this whole yay or nay debate aside, we have to assume this is normal given the wheel is not a stationary object, but a rotating one. I'm too lazy at the moment to look for studies, but I believe it got pointed out that in that region without a wing it would create a very high pressure zone, perhaps even a zone of stagnant flow. I think without a wing moving airflow away from it, it would have been nova red of color .

It also worth noting the images have inverted colors compared to one another, like you noted. However, perhaps the clue here is that the pointed areas are green, which could mean neutral pressure in both cases. Still, we have to be careful because the second image does not have a scale.

[Andres125sx]

While you keep discussing about that straw man Bhall put in front of you (nobody said a word about removing the FW or banning those airflow deflections wich reduce tire drag, and I did even said it before the discussion with rsja began), I´ll try to keep on topic, posting some unanswered questions wich, contrary to this late discussion, are related to the thread

Not on the fly, and that´s exactly the intention.

That's neither true nor relevant.

What?

It is true, you cannot change DF on the fly with traditional wings, at least that´s what you´ve been stating from the beginning. And you can with a fan as it is as simple as changing fan speed or blades pitch. Also, is relevant as that´s the problem about dirty air, drop in DF, so not sure what do you mean with this, it is true and relevant.

Airfoils make no magic, they can create a lot of DF/lift with a lot of drag, or minimize both, but you cannot create a lot of DF with very little drag. If you can patent it and you´ll be millionaire in no time.

But with a fan car you can, look at the drawing you posted on previous page, no need for any high cambered wing wich in reality is very similar to an airbrake (lots of drag), so if drag is reduced because you don´t need high cambered wings, dirty air is reduced, and the problem is reduced.

That´s posible with a fan, but not with a traditional wing, so please explain to me how that wing can be more resistant to dirty air than a fan when:

1- Any high cambered wing causes a lot more dirty air than a fan wich can be installed on a slippery (low drag) car
2- Any wing is more sensible to dirty air than a fan

So a fan is a less sensible device to dirty air than a wing, and it also reduces dirty air, two reasons in favour of a fan when compared to a wing, so please elaborate what you mean when stating a simple and giant wing is less sensible to dirty air. If you´re only comparing with current wings I´d agree, but not if you compare it with a fan.

Sorry to say this Bhall, but checking the thread it looks like you enjoy derailing the discussion, specially if we reach a point where you cannot find any reason to dislike the idea. Maybe I´m wrong, sorry if that´s the case, but that´s my feeling when I check the thread and see how many critical questions didn´t find a reply and at the same time how much time you invested talking about aspects wich are not related and nobody talked about...

When I look at the "Straw man" definition, many of your posts match it perfectly, specially the last ones talking about tire drag, steering angles and some other irrelevant (to the discussion) aspects. They´re very interesting and if a moderator split that discussion into a new thread I´ll follow it too, but they are not related to this thread and only make this thread more confusing

[Andres125sx]

I´m afraid you´re not, as I´ve only talked/asked about how to improve close racing/overtaking

My apologies then. It really came across as a case of contextual misinterpretation, but I guess I misinterpreted that myself .

Nevermind, I appreciatte the effort since my poor english has caused some confusion on previous discussions

Andres, to a go a bit more into the content (as a member and not into a moderator): it's more complicated then a plane since a plane does not have a rotating wheel behind it's wing. I wouldn't state that it does not make a difference in form/profile drag as Bhall does, but he has a point.

Well, a wing doesn´t have a continue wheel all along the width of the car either

Anycase the pictures of both canopies, open and closed, were posted with the only purpose of proving frontal area is far from the only parameter affecting drag, and current FWs are similar to an open cockpit, the windshield/flap stop at some point and at that point, the airflow will inevitably create turbulence (low and high pressure zones mixed), while a fan wing could be similar to a closed cockpit where there´s no sudden change in shape, and airflow can follow the whole contour reducing turbulence drastically

If turbulence is reduced, dirty air is reduced, and the problem is reduced, as simple as that.

[rjsa]

@ turbof1 & trinidefender - I'm sure the front wing will interfere with drag on the front wheel. Might just as well give it a tow. BUT, stating that it does not "add drag" due to not adding frontal area or even worse, reduces drag overall , doesn't have a leg to stand on.

@Andres125SX, sorry for the hijack. On the thread's question, I'm still firm on the standard GF tunnels to fight this.

[turbof1]

@ turbof1 & trinidefender - I'm sure the front wing will interfere with drag on the front wheel. Might just as well give it a tow. BUT, stating that it does not "add drag" due to not adding frontal area or even worse, reduces drag, doesn't have a leg to stand on.

@Andres125SX, sorry for the hijack. On the thread's question, I'm still firm on the standard GF tunnels to fight this.

Bhall later rectified this. He meant that the presence of a front wing will not add form drag to any other part of the car (it will add form drag in its totality of the car). It's sometimes amuzing how hefty discussions are born from an incorrectly or ambigious phrased sentence.

[rjsa]

Well, the wing IS part of the car, so that's what I was reading... never saw the OTHER

[turbof1]

Well, the wing IS part of the car, so that's what I was reading... never saw the OTHER

Hence the ambiguity. When he stressed on this a couple of times:

What I should have said, and what I've tried to clarify, is that the front wing doesn't add to the car's form drag

It hit me he implied that with 'car' he meant every other part of the car except the front wing. It's the internet missing context phenomenon. We would never have this discussion if this was being talked over in person.

To get this back on course:

Due to the aforementioned interaction with the wheels, which would be exceptionally easy to optimize with spec components, the front wing isn't an especially egregious contributor of induced drag. Because the wing has no impact on frontal area, it doesn't contribute to form drag [of the other parts of the car]. Plus, a standard front wing can be used to greatly minimize the many types of drag associated with exposed, spinning wheels...

I think that is correct in the sense you have wheel arches or an open alternative of it. Concerning turbulent airflow from the wheel this is beneficial. Mind however that I feel the wing itself should not produce downforce on its own if you want to combat turbulent wake of a car in front. So maybe it's best not to call such a device a front wing.

Using ground effect might be a solution regarding having the car generate downforce. I still stand with my opinion that ground effect cars, and in turn fan cars, would generate a massive amount of turbulent airflow, hence why it has to be combined with a big rear wing to upwash the turbulent flow, and a absence of front wing (but again, a device in front solely focussed on countering turbulent wheel wake is recommended!).