| Author |
Message |
Kristoffer Hansson (Maverick)
Junior Member
Username: Maverick
Post Number: 134
Registered: 3-2001
| | Posted on Monday, May 19, 2003 - 2:15 pm: | |
James - The "16 unknowns and 16 equations" part is mr Lucianos own words. I cant recall them all but, among other things, moments (derived from distribution of density?) and energyfunctions were used as well. I didn�t write anything down so its almost fogotten already..
"in the end it all comes down to wind tunnel time" - absolutely! Two weeks ago we had a visit from the chief of cfd for renault F1 team as well. He told us that they had four teams working with the wind tunnel. They worked in shifts so that they could run the wind tunnel 24/7...
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James P. Smith (Tigermilk)
Junior Member
Username: Tigermilk
Post Number: 135
Registered: 7-2001
| | Posted on Monday, May 19, 2003 - 12:10 pm: | |
16 unknowns and 16 equations??? Navier Stokes flow analysis (I'm a structures guy, so I may miss a few) has 3 equations with variables of velocity (3 directions), density, and the stress terms. With viscosity that's up to 9 stress components (less with stress symmetry). But those stresses can be written in terms of velocity so you're left with only velocity, pressure, density, and potentially temperature if heating is considered. Where do they come up with more unknowns? Or were they implying a fully integrated fluids-thermal-structural analysis?
Regardless, in the end it all comes down to wind tunnel time. CFD is great but there are many departures between CFD theory and real flow fields. The world is not as clean as a CFD sim. |
Kristoffer Hansson (Maverick)
Junior Member
Username: Maverick
Post Number: 130
Registered: 3-2001
| | Posted on Monday, May 19, 2003 - 11:22 am: | |
Martin - the complexity of the whole car makes problems for the teamwork, of course. They have a lot of engineering teams that are researching/constructing different things. And sometimes a certain team comes up with this great idea/construction that just must be put onto the car. But sometimes this new gimmick interacts bad with the rest of the car so that total perforamnce goes down.
It must be hard to coordinate all the different engineering teams in the same direction so that everything works out well with each other. Hats of to the gestione sportiva for succeding with that! |
Kristoffer Hansson (Maverick)
Junior Member
Username: Maverick
Post Number: 129
Registered: 3-2001
| | Posted on Monday, May 19, 2003 - 11:03 am: | |
Izel - I am studying a master of science programme in engineering physics.
Rob - Mariella stressed that he thought that the front wing was very important. This because its so near the ground. And a wing near the ground is much more efficient producing groundforce then a wing placed higher up.
Mitch - As you said, its a tradeoff of downforce versus drag. And you also have to take regulations into account. Regulations often make the search for optimal performance a hell. And when they make great progress and come up with a superb construction - FIA does not wait long before they forbid it. In an F1 car there is other aspects to have in mind as well - take the exhausts for one thing. Its hard to integrate the exhaust flow with the rear wing(s). A funny note. The first year ferrari moved up the exhausts the lower part of the wing actually melted due to the heat. So they had to put isolation on to prevent it! This is a problem of the past. Now everything is much better optimized. |
Mitch Alsup (Mitch_alsup)
Member
Username: Mitch_alsup
Post Number: 655
Registered: 4-2002
| | Posted on Monday, May 19, 2003 - 9:42 am: | |
in "Race car aerodynamics: designing for speed" Joseph Katz
The author states that a wing, properly positioned behind the car, can INCREASE the efficiency and effectiveness of the underbody diffuser. The underside of the wing creates a low pressure region, when this low pressure region is positioned at the exit of the difuser, it helps pull air through the difuser decreasing pressure and increasing downforce.
Katz indicates this is a sound tradeoff of downforce versus drag. |
Rob Schermerhorn (Rexrcr)
Member
Username: Rexrcr
Post Number: 586
Registered: 11-2002
| | Posted on Monday, May 19, 2003 - 8:31 am: | |
Kristoffer,
Thank you for sharing your experience with us! Great opportunity to gain insight into the inner team workings.
Your comment on half-serious about removing the rear wing because the under-car aero is so effective reminds me of the days when teams designed chassis without front wings because the tunnels were so effective they didn't want the front wing to disturb tunnel entry. Fittipaldi's Copersucar in '79 comes immediately to mind.
It's also refreshing to hear that Ferrari does indeed (as we all suspected) install certain components with no technical advantage, only marketing advantage. |
Martin - Cavallino Motors (Miami348ts)
Advanced Member
Username: Miami348ts
Post Number: 4666
Registered: 5-2001
| | Posted on Monday, May 19, 2003 - 7:31 am: | |
That is super interesting. I had no idea the rear wing disturbes the car. Very interesting.
Just imagine this is only one of the variables in F1 and it is so sophisticated. Add engine, electronics and all the other things and you need 30 people just to setup a car for one weekend.
Imagine, one person has to understand ALL of the variables in the car and put them together in his head. WHOW! |
izel k. (Ferrarist)
Junior Member
Username: Ferrarist
Post Number: 228
Registered: 3-2001
| | Posted on Monday, May 19, 2003 - 4:31 am: | |
Great and very interesting info. Thanks Kristoffer.
"But they used 16 unknowns and 16 equations to calculate how the airstream behaves when its passing the car. And when they do a full simulation on the car their 200 cpu and 200 GB of memory computer has to work 5 entire days to complete it." something amazing and unbeliveable for me 
What are you studying in Royal Institute of Technology?
And they win again, how great ! |
Kristoffer Hansson (Maverick)
Junior Member
Username: Maverick
Post Number: 127
Registered: 3-2001
| | Posted on Sunday, May 18, 2003 - 3:50 pm: | |
They won today as well. Man, aint they great.. |
Kristoffer Hansson (Maverick)
Junior Member
Username: Maverick
Post Number: 115
Registered: 3-2001
| | Posted on Friday, May 16, 2003 - 5:13 pm: | |
Today I got the opportunity to meet Mariella Luciano. He is the head chief of Ferraris CFD (computional fluid dynamic) for the F1 team. In other words, he is working with the aerodynamics of the car. He had a lecture at my school today (Royal Institute of Technology, Stockholm) and of course, I skipped my regular class to hear what he had to say. It was very interesting.
I will not try to explain how the Reynolds-average, Navier-Stokes equations works (I didnt understand completely anyway). But they used 16 unknowns and 16 equations to calculate how the airstream behaves when its passing the car. And when they do a full simulation on the car their 200 cpu and 200 GB of memory computer has to work 5 entire days to complete it. When Mariella started at Ferrari in 1996 they had 2 computers for CFD and he was the only one working with it (now they were seven people). Talk about difference.
In the F2003 (adding 10% lift that the car generates) 30% of the downforce comes from the front wing but it only produces 10% of the drag. 30% of the downforce is generated by the rear wing but that one stands for 30% of the cars entire drag. The flat bottom with the venturi tunnel gave 50% of the downforce and only 15% drag. Most of the remaining drag comes from the tires. He said that the rear wing almost only was there because of the the regulations (halfly joking?). The rear wing disturbs the diffuser quite alot, taking some of the diffusers downforce. Also, he concluded that the ratio between drag and downforce was high (too high?).
With this in mind I asked him about future Ferrari road cars. I wondered if they would make rear wings on any future Ferrari road car or if this belongs to the past only. He said that rear wings is useless on a road car if it has a good venturi tunnel. He said that the venturi on the Enzo was a great leap forward compared to the 360 and that putting a rear wing on the enzo was completely worthless. This since a rear wing disrupt the airflows from the diffuser. From an aerodynamic view, Ferrari will never put another wing on a road car he concluded.
From an aestethical viewpoint its possible though. If the market really wants a rear wing, maybe we�ll put one on he continued. But it would�nt add performance.
It was great to get a hint on how they work. If I want to be an engineer for Ferrari? You bet! |