Air to Bodywork energy transfer?

[DaveW]

Just for fun, the thread title made me think of this, which was first posted elsewhere in F1T. There a many F1 examples ranging from simple heave/pitch porpoising to Ferrari's infamous "vibrating front wing" where the energy extracted from the air exceeded the ability of the structure to dissipate it (overall negative damping).

[George-Jung]

No, air doesn't give energy. We all might percept air as the flowing force over the car, but it's actually the car slicing through the air. In a wind tunnel you are in fact correct.

and

Air is not a form of energy.

Just one more thing I would like to ask regarding this issue/topic;

If air doesn't give any energy or isn't a form of energy, than how about a wind turbine?

The terms wind energy or wind power describe the process by which the wind is used to generate mechanical power or electricity. Wind turbines convert the kinetic energy in the wind into mechanical power.

Source

As we all know, wind is moving air..

My question is:
When kinetic energy of moving air (wind) hits the front of the car (headwind) will this result in more downforce than stationary air will do..?

If so, than could you say that the moving air has transferred its kinetic energy in to the car being pushed harder to the ground (downforce)?

[rjsa]

Sustaining stationary air is tranfering energy to a moving car is like suggesting the tarmac is transfering energy to the car.

It's not.

Air is draining energy in the form of drag and affecting the car in the form of forces not aligned to the way of movement. Forces generated by cleverly engineered aerodynamic devices. Or not so cleverly in the case of undesired vibrations like mentioned above.

It's like saying that since a F1 car finishes Eau Rouge in a much highier elevation than it started the tarmac added potential energy to the car.

One have to chose his reference frame and system boundaries very poorly to reach this conclusion.

[George-Jung]

to reach this conclusion.

Probably you jumped to the conclusion that "I have reached to a conclusion..'
but if you'd looked a little bit more carefully, you could have seen that it was a question...

[rjsa]

to reach this conclusion.

Probably you jumped to the conclusion that "I have reached to a conclusion..'
but if you'd looked a little bit more carefully, you could have seen that it was a question...

Ohh, I was addressing the gerenic you, not you you, sorry. I didn't quote you if that makes it a bit clearer. I'll fix it.

[rjsa]

BTW, moving air does have an effect and can either add or remove enrgy from the car depending on it's direction. If it's pushing, it's adding. If it's opposing, it's removing.

The only concern is: does the car carry more os less energy due to the air effect? Energy meaning speed.

[turbof1]

BTW, moving air does have an effect and can either add or remove enrgy from the car depending on it's direction. If it's pushing, it's adding. If it's opposing, it's removing.

The only concern is: does the car carry more os less energy due to the air effect? Energy meaning speed.

Yes, indeed. Tail- and headwind are infact very big concerns for designers, or when engineers are setting up the car.

But wind starts from the assumption something else gives energy first to the air. It's like throwing a ball: a ball lying around has no kinetic energy. It only gets kinetic energy when you throw it. It might however hold energy in the form of heat - light it on fire to find out. But the interaction air-bodywork is kinetic.

F1 starts from the assumption air holds no energy; cars are being optimised to run in such air, with compromises wherever possible to not be too much disadvantage when you have to deal with wind.

[rjsa]

But wind starts from the assumption something else gives energy first to the air. It's like throwing a ball: a ball lying around has no kinetic energy. It only gets kinetic energy when you throw it. It might however hold energy in the form of heat - light it on fire to find out. But the interaction air-bodywork is kinetic.

If we move along these lines all energy comes from the big bang or the singularity that creted it. The amount being released by burning fuel included.

It's all about system boundaries.

[___]

a ball lying around has no kinetic energy

In the inertial frame of the thrower, that is true. But in the inertial frame of the solar system it has a huge amount of kinetic energy due to its velocity along the earth's orbital path.

If the physical problem you're solving is throwing the ball, then the inertial frame of the thrower is an important and relevant frame to be interested in. But if you were to carry the ball to the top of a space elevator and throw it at some passing space body on a different orbit, the energy it has in the thrower's inertial frame both before and after the throw will be negligible to the problem, while the energy in the solar system's inertial frame is crucial.

F1 starts from the assumption air holds no energy; cars are being optimised to run in such air, with compromises wherever possible to not be too much disadvantage when you have to deal with wind.

While you can think of it in these terms, it's unnecessary to think about wind as a separate problem to deal with. If you think about the car from its own inertial frame (like Mike Elliot and his colleagues clearly do) you will find that different stages of the lap subject the car to airflow with different levels of energy. Consider any one stage of the lap with a component of wind present and the energy the car sees simply varies by a small percentage, but generally only a fraction of the range that the car has to deal with in still air. The wind may make the car generate more or less downforce and drag, but the car is probably already designed to generate the maximum downforce for minimum drag that it can at that level of onset energy, so the problem doesn't necessarily need any specific design to avoid a competitive disadvantage.

Of course the nonuniformity of the wind component introduces issues that still air doesn't, but that's not fundamentally related to the amount of energy involved.