22 replies to this topic

[Jhope]

While reading this article, it occured tome that no F1 team, to my recollection, has ever used vortex generators. If it was successful on the Toyota GT-1 LPM, why wouldn't it be successful on a Formula 1 car? They are used on F-16 fighter planes, and give or take a bit, the fron of the F-16 looks a bit like the front end of a Formula-1 car.

[Ben]

If a barge board isn't a vortex generator, I don't know what is.

Ben

[Jhope]

ya know...i feel kinda stupid right now... :

[BRIAN GLOVER]

Vortex generators, or as the airforce now calls them, boundary layer energizers, are those little tabs,measuring about 3cm*2cm, that are placed perpendicular to the upper surface of a subsonic airfoil or wing, and 15 degrees from the relative wind, from the point of separation of laminar flow in high angles of attack conditions, and rearward toward the flap and aileron.

They are found on high laminar flow wing sections or high loaded, sub sonic wings.
You wont find them on a DC3 for instance, but usually executive jets. Early Lears would stall at altitude if 10% of these generators where missing, numbering up to 100, because of insufficient thrust to keep the wing within its design envelope.
Most subsonic aircraft do not have sufficient thrust to maintain optimum angles of attack at or near their service ceilings and a careful monitoring of an A of A meter is necessary to prevent a stall in turbulent air. Flight must continue at a lower altitude. These devises extend the boundary layer, by re attaching it to the surface.
Fighter planes since the F11 have energized this surface by other means, such as artificially lowering the pressure by bleed offs from one or two stages of the compressor turbines causing the layer to be sucked onto the wing surface via thousands of tiny little holes on the surface.

As I said this is for slow flight and high A of A regions where drag is not a primary consideration. This method creates less drag than the above and these tabs would present flow problems at supersonic velocities.

I cant see why you would want to create drag on a race car according to this article. They compare it to this multi task aircraft in slow flight.

The barge boards, actually ramps, found on F1 cars, prevents turbulence from the front wheels entering the pods and in the case of aircraft, these splitters or ramps, sometimes variable(vari-ramps) separate clean air from the dirty air in the boundary layer on the surface before entering the intakes. I think what we are seeing on these cars is more management of turbulent air, rather than the creation of it.

Originally posted by Jhope
While reading this article, it occured tome that no F1 team, to my recollection, has ever used vortex generators. If it was successful on the Toyota GT-1 LPM, why wouldn't it be successful on a Formula 1 car? They are used on F-16 fighter planes, and give or take a bit, the fron of the F-16 looks a bit like the front end of a Formula-1 car.

[12.9:1]

Jhope

Don't get your hopes up, just yet

.

[Ben]

Originally posted by BRIAN GLOVER
Vortex generators, or as the airforce now calls them, boundary layer energizers, are those little tabs,
The barge boards, actually ramps, found on F1 cars, prevents turbulence from the front wheels entering the pods and in the case of aircraft, these splitters or ramps, sometimes variable(vari-ramps) separate clean air from the dirty air in the boundary layer on the surface before entering the intakes. I think what we are seeing on these cars is more management of turbulent air, rather than the creation of it.

I agree that keeping the turbulent wake from the wheel away from the radiators is an issue, but if you look at a barge board it is curved in plan view and has some of it's face presented to the oncoming air. As far as I can see this will generate high pressure on the front face, low pressure on the rear face, which will result in a vortex forming over the board.

The overall curvature of the board will take the airflow out around the sidepods, but I think the vortex that will be created plays an important role in controlling the lateral flow under the sidepods. With relatively small diffusers these days it is probably a design goal to reduce the flow of air under the car to ensure that the diffuser isn't supplied with more air than it can diffuse. A vortex running alongside the car would surely draw air into it and reduce the amount migrating under the car.

Just my thoughts anyway - it's difficult to speculate though without any test data.

Ben

[12.9:1]

Sorry off topic,- but I have a photo of some really nice decorative trim, on an unusual looking red car.

[Jhope]

Originally posted by 12.9:1
Sorry off topic,- but I have a photo of some really nice decorative trim, on an unusual looking red car.

I was thinking of these at work today, and how I read that they create vortecese (sp?) which are forced under the car. As well, behind those bargeboards, Ferrari have a small black tab similar to the ones on the barge boards, and it is thought to have the same function as the barge board edges.

[CdnF1Fan]

Originally posted by Jhope


I was thinking of these at work today, and how I read that they create vortecese (sp?) which are forced under the car. As well, behind those bargeboards, Ferrari have a small black tab similar to the ones on the barge boards, and it is thought to have the same function as the barge board edges.

Although many people believe the main purpose of Barge Boards is to direct air into the sidepods, their primary purpose is to generate vortices that swirl beneath into the flat bottom region (of the car). Vortices - being like mini tornadoes - are of low pressure. And, when routed under the car ... produce downforce.

The prongs on the Ferrari bargeboard 'tune' the airflow (vortices) in a manner that results in several different vortices generated off of each of the barge boards. Further, the length of these 'prongs' can be use to stabilize the vortices to prolong their energy as far aft as possible. Hence what you see are 'tuning prongs' that effectively generate longer vortices under the car , until they ultimately destabilize into wake. At this point the rear diffuser takes over.

I'd go as far as to say these tuning prongs gave the F2002 much of the aero-advantage they had over the rest of the field last season, and can only wonder if the other teams, had they the use of two 24-hour-a day / 7 days per week Windtunnels, might have come up with similar designs?

CFF

[Bladrian]

What I, as a South African, enjoy is that three top racing designers (Rory Byrne - Ferrari, Gordon Murray - McLaren and Pierre Terblanche - Ducati) are all South Africans ..... it must be somethiong in the beer.

[Ben]

The suggestion that these vortexs produce downforce because they create low pressure is wrong.

The reason you would want to induce turbulent flow (a vortex) under the car is that a turbulent flow will energise the boundary layer and create lift by delaying flow separation.

Ben

[BRIAN GLOVER]

I don't think that the ramps or BBs are there to direct air into the sidepods.
I think during wind tunnel tests, they found the air going into the sidepods was sufficiently turbulent as to reduce cooling efficiency and also, some of this flow is used for creating downforce within the sidepod itself which requires smooth air and the flow around the wheel without the ramps, would impede this flow.

The ramps may even have been put there to stop stones and other debri from entering the sidepods and they accidently discovered that it had other properties while playing in the wind tunnel.

The huge gap between the ramp and the intake would render any intentional vortex generation to be ineffective anyway, otherwise they would have put those teeth directly under the intake.
On the other hand, this gap, in conjunction with the teeth, may cause a vortex under the sidepod.

Since the designers are restricted in the manor in which they create downforce, they trade off some vortex drag for downforce. Who knows?
In the case of aircraft, these artificial methods of containing the boundery layer, is only at the bottom of the aircrafts performance envelope, whereas in the case of F1 car, to generate vortices at the top end of its design envelope, still doesnt make a lot of sense to me.

An observation: The speeds of the F1 car and the aircraft at these two extremes, are about the same.

I think by placing these BBs where they are, they encounted some severe turbulence with the overflow and tried to minimise or control it with those teeth like protrusions.

However, if this is the case, then why did they not place a flange along the bottom edge of the ramp, instead of those teeth things?

Somebody on this NG has gotta do better than this. Where are the aero guys?

Another thing that bothers me, having been involved with experimental aircraft construction, there is a lot of parasitic drag coming from the atachment points of the suspension also, which to my mind causes unnessary turbulance. I cant understand why there aren't farings at these points.
I'm getting more confused than ever.

[QUOTE]Originally posted by CdnF1Fan
[B]

Although many people believe the main purpose of Barge Boards is to direct air into the sidepods, their primary purpose is to generate vortices that swirl beneath into the flat bottom region (of the car). Vortices - being like mini tornadoes - are of low pressure. And, when routed under the car ... produce downforce.

[desmo]

I am no aero boffin to be sure, but I have been told as well that the primary role of BBs now is indeed to act as vortex generators. I assume that they function as well to direct the turbulent wakes from the front wheels and wing endplates away from the aero package downstream.

BG: "The huge gap between the ramp and the intake would render any intentional vortex generation to be ineffective anyway, otherwise they would have put those teeth directly under the intake."

I think you'd find that there are indeed a similar set of "teeth" in front of and below the intakes on the F2002, although I don't have a link to a photo handy. Indeed, a look at this year's BB and turning vane designs shows lots of evidence of intentional vortex generation. Look at some of the sharp angles and corners that have appeared, particularly on the Jordan and Williams designs further forward on the chassis, and the "3D" or "biplane" details of the more conventional BBs on other cars.

[Bladrian]

'Boundary layer energizers' as Brian noted, is the correct function of these vortex generators. The ubiquitous Gurney tab, or flap, does exactly the same thing - decreases boundary layer separation, thus increasing the efficiency of the airfoil it's attached to.

[Aubwi]

With that horizontal plane attached to the bottom of the bargeboard, would that actually produce downforce on the bargeboard structure itself? Higher pressure above the plane and lower pressure below? Same effect as a "splitter" on a sports car?

[DOHC]

Originally posted by desmo
I think you'd find that there are indeed a similar set of "teeth" in front of and below the intakes on the F2002, although I don't have a link to a photo handy.

Here:
http://www.atlasf1.c...mage/IMG_2697-3

It was discussed in this thread after Monaco.

[Eau Red]

the 2001 BAR (and I think the 2002 also) had almost-horizontal tabs protruding from either side of the nose, with cutouts in the center. Those must be vortex generators...

CdnF1Fan- the F2002 had two of its most dominant races-- Imola and Barcelona-- before the serrated barge boards appeared. So they probably weren't a huge part of what made the car so fast.

[BRIAN GLOVER]

...and still not completely resolved. I wonder what the speed range is that they would be most effective?
Would they tune it for 130R in Japan, or would it be effective elsewhere on the track? Are they different from track to track. How will they work in the rain or other atmospheric variations? How about yaw and traffic conditions?

Originally posted by DOHC


It was discussed in this thread after Monaco.

[desmo]

http://www.news-pub....r07/052312l.jpg

Here's a link to a nice view of the serrations forward of the sidepod radiator intakes on the F2002 from Kenji Sawada's website.

[Chickenman]

"Competition Car Downforce" by Simon McBeath ( ISBN0854299777 ) explains on page 102-103, the purpose of creating rolling vortex's along the sidepods of modern F1, Indy and Sports cars. A rolling vortex creates an " Air Curtain " thus preventing the leakage of some air to the underside.

Indy cars, never being allowed side skirts, became very proficient at this type of side sealing.

Edit: Spelling

[RDV]

it occured tome that no F1 team, to my recollection, has ever used vortex generators

they were used extensively on venturi throats of Wing-cars in the late 70`s and early 80`s

[DOHC]

Originally posted by BRIAN GLOVER
...and still not completely resolved.

I belive that this is a question of considerable interest in F1 aerodynamics. As I'm no aero expert, I am curious about understanding the general principles behind the vortex generators (in the many different shapes they're used) in F1.

I'd like to revive this thread with a number of examples, which look more or less like vortex generators.

McLaren's MP4/17 has what I would call two vortex generators on either side of the rear end of the cockpit sides' head protection "bulges." I would guess that those vortex generators are there to energize the boundary layer over the slanting engine cover, so as to avoid the flow from detaching and becoming overly turbulent.

But there are many other kinds of "vortex generators." In Canada this year, Ferrari ran "strakes" on the nose cone, see the device in this picture on the right side of the nose cone, across the Vodaphone logo. This kind of strakes are often seen on the engine nacelles of e.g. B737 (the new versions, with the wide turbofan engines) and other commercial jets, also on other parts of the body, e.g. on the lower side of the nose of the MD80 series of jets. Why do Ferrari use them, and why only in Canada, and why only in the race? (I may be wrong on this, they may have used them on several other occasions.) It seems to me that this strake is intended to create a vortex from its tip, possibly to ease up flow across the upper wishbones.

Another similar feature is the the strakes we find on front-wing end-plates. Williams have used an almost triangular strake on the insides of the end-plates (although I think Sauber started using them). On the outside, a bent strake is common since a few years back. The extensive use of this kind of strake indicate major aerodynamic problems at the front wing's ends. Of course, this should be quite clear. After all, the end-plate is very close to the wheel, and it is impossible to get a clean flow there.

The side-pod flip-ups are also a kind of bent strake. There are two kinds: the real flip-up which starts from two-thirds up on the side pod, and the free-flow strake elements on top of teh side pods, as used by e.g. Jaguar (Ferrari are using winglets there, and no strakes).

I don't know if this rather large heap of questions will make things more clear. But to me it seems that vortex generators and strakes are becoming ever more popular, although I think that they all must have a fairly considerable drag penalty.

Any comments?

[DOHC]

New barge board/vortex generator on Williams car at Jerez.