February Test Thread

[Jersey Tom]

The wind tunnel I'm thinking of puts that BMW one to shame

Though you can't fit multiple cars I don't think. But it is FULL scale, and the whole road moves as well as the car.

[tk421]

I can think of at least 1 full-scale rolling road wind tunnel for which this is not true. The wind tunnel I'm thinking of puts that BMW one to shame

So spit it out already! Unless it's confidential...

[Jersey Tom]

http://www.windshearinc.com/

[modbaraban]

http://www.windshearinc.com/

That's the one USF1 are going to use as far as I've heard.

[Shredcheddar]

Mario Thiessen said it in the video, as Myurr and others have in this thread. CFD and wind tunnels are tools. Even with gigaflops of computing power, or a 60% scale yaw-capable rolling road wind tunnel, there are limitations and flaws to each tool. So real-world verification is both desirable and (for lesser series with fewer "secondary" testing opportunities) a way of getting results that you are extremely confident in.

That said, real-world flow visualization has its drawbacks as well, as has been duly noted in this thread. So ideally a combination of all three yields the best results.

I can't say why no other teams have been using this (or so it appears). My best guess (guess!) is that with major aerodynamic regulation changes, there is less knowledge about how, for example, a change to the front wing affects flow around the (very different) body work. Like I said, that's a guess. I have no idea how valuable real-world visual verification of aerodynamic performance is to a Formula 1 team.

[kilcoo316]

My guess is that its PSP - Pressure Sensitive Paint, used to validate existing windtunnel and CFD work. Why do it outside rather than in the tunnel? Well do you want the tunnel to be out of action after every test while its getting cleaned?

How accurate is PSP?



I've seen RMS difference between taps and paint of 1,500 Pa for subsonics - what use is that in validating anything?

(to put it into perspective, at 80m/s that can be a Cp of 0.38!!!)

[i70q7m7ghw]

LOL, the teams thought they were clever going to Bahrain to test because it couldn't possibly rain there... can you say sand storm?

[kilcoo316]

The wind tunnel I'm thinking of puts that BMW one to shame

Err... I think its quite similar to the Hinwil tunnel actually.



Both capable of 180 mph speeds...

Both capable of full scale cars...

Both capable of taking 2 scaled cars...

[kilcoo316]

Everyone here, for all their expertise, seems to be forgetting that in a rolling road wind tunnel, the car is always facing into the wind.

WHAT?!?!


Every wind tunnel worthy of the name since the early 90s has been able to yaw the car on a rolling road!

[slimjim8201]

I don't think it is exactly pressure sensitive paint. PSP appears to change certain optical properties under various loads. Check it out...

http://www.aerospaceweb.org/design/psp/main.shtml

The paint McLaren are using may be a bit simpler. Areas of high shear stress cause paint movement and relocation (or removal)? Areas left behind are high pressure zones, stagnation regions, and streaking that show local air direction near the surface.

As far as those calling it out as useless, if one can look at it and wonder about what the air is doing in a certain region because of the way the paint has moved, then it is useful. Any form of flow visualization is useful, CFD, windtunnel, paint, <insert new technology>.

[kilcoo316]

As far as those calling it out as useless, if one can look at it and wonder about what the air is doing in a certain region because of the way the paint has moved, then it is useful. Any form of flow visualization is useful, CFD, windtunnel, paint, <insert new technology>.

As you said (without really meaning to), pretty much all you can do is look at it and say, oh, its going from A to B... isn't that nice.

No pressures, no velocities, no nothing. All you can do is look at it and wonder exactly what is happening.


I'm sure there is a reason behind it that I'm not getting - they didn't do it for the fun of it - but I don't see it providing anything useful to validate their tunnel or CFD - unless both are qualitatively out by a big margin (and as we both know - if that is the case - they are well and truly f**ked!).

[djos]

RB5 still the quickest '09 car at Jerez but this time it's Webbo and he's even faster thatn Vettel was yesterday!

1. S. Buemi Toro Rosso Toro Rosso STR3 1:18.703 44 pit
2. M. Webber Red Bull Racing Red Bull Racing RB5 1:21.321 +2.618 +2,618 24 pit
3. H. Kovalainen McLaren MP4-24 1:21.324 +2.621 +2,621 23 pit
4. N. Piquet Jr. N. Piquet Jr.. Renault R29 1:22.826 +4.123 +4,123 9 pit
5. K. Nakajima Williams FW31 1:22.827 +4.124 +4,124 18 pit

[chasefreak]

this paint thingi was used last year too to understand the air flow over the front wheels caps... so dis is not something new for mclaren

[Scotracer]

As far as those calling it out as useless, if one can look at it and wonder about what the air is doing in a certain region because of the way the paint has moved, then it is useful. Any form of flow visualization is useful, CFD, windtunnel, paint, <insert new technology>.

As you said (without really meaning to), pretty much all you can do is look at it and say, oh, its going from A to B... isn't that nice.

No pressures, no velocities, no nothing. All you can do is look at it and wonder exactly what is happening.


I'm sure there is a reason behind it that I'm not getting - they didn't do it for the fun of it - but I don't see it providing anything useful to validate their tunnel or CFD - unless both are qualitatively out by a big margin (and as we both know - if that is the case - they are well and truly f**ked!).

Maybe they use it to determine areas for closer examination via CFD. Anything that can narrow down your problem areas is good!

[Roland Ehnström]

RB5 still the quickest '09 car at Jerez but this time it's Webbo and he's even faster thatn Vettel was yesterday!

1. S. Buemi Toro Rosso Toro Rosso STR3 1:18.703 44 pit
2. M. Webber Red Bull Racing Red Bull Racing RB5 1:21.321 +2.618 +2,618 24 pit
3. H. Kovalainen McLaren MP4-24 1:21.324 +2.621 +2,621 23 pit
4. N. Piquet Jr. N. Piquet Jr.. Renault R29 1:22.826 +4.123 +4,123 9 pit
5. K. Nakajima Williams FW31 1:22.827 +4.124 +4,124 18 pit

Well, everyone is faster today (better track conditions I guess), and Kovalainen has gained the most, virtually equalling Webber's time. Piquet still 1.5 seconds off the pace, and has driven the fewest number of laps again.