# Downforce-aerodynamics-fluid dynamics *Challenge*

1. Jul 11, 2017

### Iceracer33

In basic car aerodynamics car manufactures know the basic design in every car creates lift. Let's take the Prius for example, very aerodynamic but does not have any downforce due to the shape of the vehicle (air travels farther on top of the car) being shaped like a wing of an airplane. My challenge is to take away length of an air wave and replace it with pressure to make downforce on that same vehicle without using the typical air dam or spoiler in front. Let me explain, I believe I may be able to produce downforce by 1. Ramping air (accelerating) under the car at the front to create a higher pressure under the car. 2. Flat bottom with or without a slight rake to the car 3. A rear diffuser.

Now wait, before you go on the "do it this way because it works" train I would like to express that "I know" and "I don't care" about that at all, I know that works and works well but that does not answer my question.

Hear is my equation: take the Prius, let's say it looks like a wing and will produce lift, okay. Fluid dynamics says if you create a high enough pressure under the car it will produce downforce (even the weather man knows high pressure will go to low pressure) I may have said that backwards. "Bernoulli's principle".

WITHOUT reducing air (air dam or spoiler) and only "accelerating" air can you make downforce on that car?

F1 cars back in the 80's used this same principal and only stopped using it because the rules told them so. I have no rules to abide by because this is my own experiment and will not race in any certain class.
So, the way I see this is like this: first take two spoons and tape them together so you have a fulcrum and an egg. If you put them in water with a string at the end of the fulcrum, the spoons will fall (gravity). Now accelerate the water to where the spoons are at least at a 45degree angle (still gravity kicks in) without any floor or ceiling being a part of the equation. Now, without moving the floor move the ceiling down slowly toward the spoons. At some point the spoons will want to be "sucked" twords the ceiling. Now acelerate the ceiling like it was the road under you (creating even higher pressure), wouldn't the spoons want to stick to the ceiling?

Can I create this even in some small fashion on my car and "then" add the extra stuff to create even more downforce without sacrificing ride height? I know that adding a spoiler, shocks, tires and all that other stuff works and I don't discredit that at all but again, that doesn't answer the "air pressure" question. Thank you.

Last edited by a moderator: Jul 12, 2017
2. Jul 13, 2017

### JBA

You counter the lift due the low pressure over the top of the car by creating a low pressure region by accelerating the flow under the car, not a high pressure one.