Pup wrote:Kinda-sorta.
The thing is that if you look at the car as a whole, any increased drag produced by a better diffuser can be countered by reducing the wing - net result being either more downforce or less drag or both, you pick. Of course, the two are somewhat dependent on one another. The diffuser works in large part because it exits into a low pressure area created by the car and wing, so you might say that it is dependent on drag.
Having said that, here is an interesting post from a few years back that shows how introducing a diffuser actually decreases the overall drag on the car. It wasn't discussed further, but its interesting, despite being somewhat beyond my understanding...
http://www.f1technical.net/forum/viewto ... 39#p164039
So, one might argue that the diffuser is not only drag free - it's drag negative.
Actually, understanding the drag of a car is easy, and goes completely in line with the function of the diffuser (I hope I get the wording correctly here):
The drag of a motor vehicle (or any moving object) is the difference in pressure in front and behind the vehicle. The larger the pressure difference, the higher the drag. Basically you are displacing a medium (air), which rushes back to fill the void created by the vehicle. The common name for this effect is suction - the car is also being sucked into the low pressure area it created.
The diffuser is a tool to increase pressure. Basically it takes the flow of the fluid and decreases its speed by increasing the area through which it flows, which increasing the pressure. It also controls the pressure increase at its exit (versus a radical increase at the end of a plate, which causes extreme turbulent flow). The effect is the same as in a fast flowing creek which widens into a river - it slows down. Important: the actual diffuser effect is generated through the angle of the diffuser between the road and the car, not across the width of the diffuser. The additional elements help keep the flow smooth, but do not actually add pressure. The increase in downforce comes from the flow being smooth at the end of the floor, allowing more flow to pass under the car.
So, to sum it up: the diffuser increases the pressure smoothly behind the car (drag down) and evacuates the air from under the car (downforce up). For cars the perfect aerodynamic tool, which is why they have been limited so much by the rules.
Hope that was clear.....
“Strange women lying in ponds distributing swords is no basis for a system of government. Supreme executive power derives from a mandate from the masses, not from some farcical aquatic ceremony!” Monty Python and the Holy Grail
Others pictures with the upgrades?
