Laminar Flows, Cash, Money, and Speed
Been drooling over the new Ferarri F2005, which they're debuting attheBahrain GP. The aerodynamics intrigued me, so I sent this email to a mechanical engineer and physicist I know named Juan. Note that I don't actually know any physics, but if anybody else does, please let me know if this makes sense...
"BTW, the new Ferarri looks iller than Terri Schiavo on a bad day. I guess the swooped radiator scoops are pretty much standard F1 gear this year, and it’s a good thing; they’re harde as nails. Of particular interest to me on the new Ferarri were (1)the front mini-wing, and (2)the double(?)-slotted airfoil on the main front wing. Airfoil design is supremely wicked, by the way, whether for scale aviation or F1 purposes.
"Take a look at this picture, for instance. My guess is that the mini-wing in front of the main front wing is supposed to reduce turbulence on the under-tray. One of main things with wing functioning is the concept of laminar flow. Basically, laminar flow is the opposite of turbulence. As you can see from the link, when you have a fluid (in this case air) moving between a stationary and a moving plate, the air near the moving plate moves gradually faster than that which is nearest to the stationary one. In this condition, the air is streamlined. So, in this case, the stationary plate obviously would be the track surface, and the moving one would be the undertray. The problem is that the MAIN front wing, with its downward angle of attack, would create a Bernoulli effect, or basically a turbulent vacuum, on the underside and trailing edge of the wing. That means that the air entering under the car would be turbulent and not streamlined, resulting in a potential and obviously wildly catastrophic nominal loss of Speed.
"My bet is that those mini-wings, which look to have a neutral angle of attack, are basically fins that focus a 1-foot wide flow of streamlined, laminar air under the car to offset the turbulence from the main wing. There are probably groovlets under the car to help this. Another effect might be to narrow the angle at which the wind attacks the main wing, the way a jib does for a mainsail. The benefit is that more wind would hit the main wing exactly dead-on, so you could calculate the critical wing angle more precisely. That said, the wind probably already hits the wing pretty much dead on, unless you’re drafting.
"As for the slotted airfoils, apparently they creat lift (or downforce here) more efficiently than constant airfoils. They use them in flaps in airplanes sometimes, and also in helo rotor tips. I think there’s some thing with stall characteristics, which don’t really apply to car wings, that makes them not always suitable for plane wings. When I was a lab assistant (biology) at ______, another guy (physics) was wind-tunnel testing slotted airfoils. We used to smoke a lot of herb together in the science building.
"Anyway, if the builders don’t do it already, I’d bet that at some point they start messing around with actively heated and cooled wing surfaces. Apparently that affects flows a lot, too.
"One thing I don’t really get is the upward-swooping air scoops on the side of a lot of this year’s cars. They look money, but from their appearance, I’d think they actually create lift. Check out this shot of Alonso’s whip. It would seem like the air enters at the “N” in Mild Seven, then runs into a surface with a positive angle of attack (inside, along the tops of the letters “SEVEN”). True, the airflow is then directed down, maybe in a vortex of some kind, but I don’t know where it goes after that. Maybe they just needed the scoop opening to be higher in relation to the front tyres than it used to be, and they can’t position the body of the scoop any higher…"
"BTW, the new Ferarri looks iller than Terri Schiavo on a bad day. I guess the swooped radiator scoops are pretty much standard F1 gear this year, and it’s a good thing; they’re harde as nails. Of particular interest to me on the new Ferarri were (1)the front mini-wing, and (2)the double(?)-slotted airfoil on the main front wing. Airfoil design is supremely wicked, by the way, whether for scale aviation or F1 purposes.
"Take a look at this picture, for instance. My guess is that the mini-wing in front of the main front wing is supposed to reduce turbulence on the under-tray. One of main things with wing functioning is the concept of laminar flow. Basically, laminar flow is the opposite of turbulence. As you can see from the link, when you have a fluid (in this case air) moving between a stationary and a moving plate, the air near the moving plate moves gradually faster than that which is nearest to the stationary one. In this condition, the air is streamlined. So, in this case, the stationary plate obviously would be the track surface, and the moving one would be the undertray. The problem is that the MAIN front wing, with its downward angle of attack, would create a Bernoulli effect, or basically a turbulent vacuum, on the underside and trailing edge of the wing. That means that the air entering under the car would be turbulent and not streamlined, resulting in a potential and obviously wildly catastrophic nominal loss of Speed.
"My bet is that those mini-wings, which look to have a neutral angle of attack, are basically fins that focus a 1-foot wide flow of streamlined, laminar air under the car to offset the turbulence from the main wing. There are probably groovlets under the car to help this. Another effect might be to narrow the angle at which the wind attacks the main wing, the way a jib does for a mainsail. The benefit is that more wind would hit the main wing exactly dead-on, so you could calculate the critical wing angle more precisely. That said, the wind probably already hits the wing pretty much dead on, unless you’re drafting.
"As for the slotted airfoils, apparently they creat lift (or downforce here) more efficiently than constant airfoils. They use them in flaps in airplanes sometimes, and also in helo rotor tips. I think there’s some thing with stall characteristics, which don’t really apply to car wings, that makes them not always suitable for plane wings. When I was a lab assistant (biology) at ______, another guy (physics) was wind-tunnel testing slotted airfoils. We used to smoke a lot of herb together in the science building.
"Anyway, if the builders don’t do it already, I’d bet that at some point they start messing around with actively heated and cooled wing surfaces. Apparently that affects flows a lot, too.
"One thing I don’t really get is the upward-swooping air scoops on the side of a lot of this year’s cars. They look money, but from their appearance, I’d think they actually create lift. Check out this shot of Alonso’s whip. It would seem like the air enters at the “N” in Mild Seven, then runs into a surface with a positive angle of attack (inside, along the tops of the letters “SEVEN”). True, the airflow is then directed down, maybe in a vortex of some kind, but I don’t know where it goes after that. Maybe they just needed the scoop opening to be higher in relation to the front tyres than it used to be, and they can’t position the body of the scoop any higher…"
posted by HAKKIN£N!!!!!!!!!!!!! at 01:12
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