i have just seen the article about renault's paint job on the new chassis,the specialist said that it is important that the parts are as slick as possible,
this made me think of why would one want the surfaces to be absolutely slick??
swimmers have started using special suits named''shark skins'' the coating on these suits are made of tiny ripples which appear to help have a better penetration of the water,why is it not adopted in f1??
I'm thinking that water and air act as two different fluids so a slick surface will probably allow air to travel more easily around the surface as opposed to somethign w/ sticky things, I dunno.
BTW at the USGP Renault left the front of their rear wings unpainted; according to Steve Machett (Speed TV commentator and F1 Racing writer) it gave a better airflow over the rear wing.
Well golf balls actually, or more accurately the dimpled surface that helps them fly further and true. I have always wondered how this works but also if the theory coud be used on some of the aerodynamic surfaces of a GP car
As far as I know, the ribbles on the shark suits hold a small layer of water on them, so the friction when swimming is between the water and that layer of water on the suit.
This means there is a lot less friction, so the swimmers go a lot faster.
I don't know if this works the same with air.
What they do have with air, are those ribbled rear wings ^(a little like this ^^^^^^), this creates vortexes (sp?) so the slipstream behind the car (the vacuum) is being filled up, so the car is less sucked back by the vacuum.
This was first used in ice-skating!
Hope I could make myself understandable a little, as English is not my native language.
Location: Covilhã, Portugal (and sometimes in Évora)
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the dimples on the golf ball produces a turbulent boundary lawer with reduces the drag produced by the ball......in a Formula 1 car if you reduce the drag produced by it you'll also be reducing the downforce the is produced.....
Location: Covilhã, Portugal (and sometimes in Évora)
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in a swimmers case or in a golf ball you don't need the downforce or the lift so you can reduce the drag to the limit.....which be very helpfull....in a formula 1 car....it won't really help you....in a straight line yes......but when you reach a fast corner it won't help you at all.
I don’t know how relevant this is but NASA has done some testing on this kind of thing, they took a material of some sort with millions of tiny holes in and attached it to part of a F/A 18 Hornet's wing. As the plane got faster the air surrounded this material and created some kind of air bubble round it, which was almost fiction less. I think they said that it would allow a plane to accelerate more quickly and using less fuel, they also noticed that the air was moving slightly faster over the wing so there was more of a pressure difference so the wing can generate more lift.
Location: Covilhã, Portugal (and sometimes in Évora)
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Yup...some air planes have one the upper side of the wings something that has the same kind of texture as sandpaper in order to reduce drag, by converting the boundary lawer from laminar to turbulent as close to the front as possible, a turbulent boundary lawer produces less drag then a laminar one.....joseff....actually what you said is a good idea.......the helmet...but that could disrupt the air going into the airbox......and underneth the car it could also disrupt the airflow to the difusser and radiators.....but it's "try-able".....one day it might be used......who knows.
A smoother paint job reduces skin friction and improves the boundary layer. The flow of air over an object can be considered similar to the old trick we all learnt about fricton between two solid surfaces at school!!! remember, we used a sheet of material at a slope and but a block on it, it shown that the friction between to surfaces is less when a smooth surface is used, and high when rough surfaces are used. So if a smooth surface is used the friction between the air flow and the object is less, and the boundary layer does not thicken as quickly (do you know how the Boundary layer works???)
The shear force of the air flow is calculated using,
t = Cf (0.5 x rho x V^2)
where t = the shear force
Cf = skin friction coefficient
rho = Density (or the fluid)
V - Velocity
Its has also been mentioned of using rough strip surfaces, these are used extensively on scale model testing in wind tunnel. When testing a scale model in a wind tunnel it is important to ensure flow similarity is preserved. So using the various scale calulations (using reynolds number, etc) it may be found that the wind tunnel needs to be run at a very very high speed, if this is not possible then rough strips are used, known as "trip strips" that trip the Boundary Layer at the transition point on the model (calculated) and so provided flow similarity.
There is alot more in it than this but gives you the idea.
A smoother paint job reduces skin friction and improves the boundary layer. The flow of air over an object can be considered similar to the old trick we all learnt about fricton between two solid surfaces at school!!! remember, we used a sheet of material at a slope and but a block on it, it shown that the friction between to surfaces is less when a smooth surface is used, and high when rough surfaces are used. So if a smooth surface is used the friction between the air flow and the object is less, and the boundary layer does not thicken as quickly (do you know how the Boundary layer works???)
The shear force of the air flow is calculated using,
t = Cf (0.5 x rho x V^2)
where t = the shear force
Cf = skin friction coefficient
rho = Density (or the fluid)
V - Velocity
Its has also been mentioned of using rough strip surfaces, these are used extensively on scale model testing in wind tunnel. When testing a scale model in a wind tunnel it is important to ensure flow similarity is preserved. So using the various scale calulations (using reynolds number, etc) it may be found that the wind tunnel needs to be run at a very very high speed, if this is not possible then rough strips are used, known as "trip strips" that trip the Boundary Layer at the transition point on the model (calculated) and so provided flow similarity.
There is alot more in it than this but gives you the idea.
Generally speaking :
Drag (total drag) is generated by the sum of three components : friction drag (air friction on the surface), pressure or form drag (related with the wake and so with the shape of the body) and induced drag, caused by the generation of lift. The latter could be reduced via different designs of the wings.
Golf balls dimples (also seen sometimes on the helmets of cyclists) works on the pressure drag. Monstrobolaxa got it right about the golf ball (the remaining part of his post on the contrary is debatable at best), the dimples forces the boundary layer transition, so the b.l. becomes turbulent at a speed lower than with a smooth surface (that speed would be indeed higher than the typical speed of a golf ball). That’s important to observe, transition happens anyway over a certain speed or after a certain distance from the leading edge, you will use dimples, rough paper or whatever else just to force it to happen earlier (in term of speed or of position in the body). Turbulent b.l. is less inclined to separation than a laminar one, so the b.l. separation is delayed and the size of the wake reduced => lower pressure drag. Correspondently this increases friction drag but the total drag is lower anyway.
The fact that smooth surface is the best for friction drag isn’t completely true. Shark skin (and similar passive devices on the surfaces like riblets) indeed works on the friction drag, reducing it while interacting with small scale turbulent structures close to the wall. The contribute of friction drag in case of swimmers (or of sharks...) is very high (shear stress is proportional to viscosity and viscosity of water is 100+ times bigger than viscosity of standard air) so its reduction becomes quite important.
In case of skaters pressure drag is again important and, although I’ve heard that also them uses “shark suits”, the suits have also some little bulges on the head and in other parts of the body to force the transition of the boundary layer, just as dimples on the golf ball. I’ve seen them first time in Nakano Olympics games IIRC, don’t know if still in use or not. Also, a team in the 250 GP class used once in 2002 a few thick and serrated stickers on the fairing to force the transition, I do remember a pic I’ve seen on a magazine, I’ll search it but I think they were just in front of rider’s hands.
At the end the “ribbled rear wing” as described by the “future member” is simply a serrated gurney flap, working with the same concept as a standard one but according to some source a bit more efficient, in F1 it has been adopted by Williams on the rear wing flap and also in the McLaren front flap a few years ago. It has nothing to do with the riblets I mentioned above and I doubt it could help to “fill the vacuum” behind the wing because the axial vortices generated are probably very small and have a very limited life (in term of distance from the trailing edge).
So, to answer the original question, a system to reduce drag has to be chosen in function of which kind of drag is predominant, of the typical speed of your vehicle (more correctly, of the range of Reynolds numbers) and in relation with your possibilities to modify the shape of the body (golf ball is a ball and also is rotating so you can’t modify the shape, you have to work in a different way). In case of F1 the use of shark skin would difficulty make a big difference, especially on the single lap, because friction drag isn’t very important in term of total drag and you have also to consider that a F1 bodywork never ends the race as clean as when it started it dramatically reducing the efficiency of the surface treatment.
but also if the theory coud be used on some of the aerodynamic surfaces of a GP car 
