Rear Wing Idea

[hollus]

Unless I haven´t followed correctly, you guys are talking about two different types of infinite span wings, with confusion arising from using the same name.
One type has infinite wingspan and a realistic angle of attack, and it produces an infinite amount of lift.
The second type has infinite span and creates a finite amount of lift. This one has an infinitesimally small angle of attack.
I think trinidefender is implicitly talkig about the first, while most others are implicitly talking about the second, am I correct? I hope this helps find common ground.

Coming from a completely different background: The law of conservation of energy demands that any wing, infinite span or not, that pushes air downwards, must pay a drag penalty. Here is where the wing with the infinitesimally small angle of attack can, in theory, get away with murder and zero drag (infinitesimally small, to be exact). Shoot me down if I am completely missig the point, please.

[trinidefender]

Unless I haven´t followed correctly, you guys are talking about two different types of infinite span wings, with confusion arising from using the same name.
One type has infinite wingspan and a realistic angle of attack, and it produces an infinite amount of lift.
The second type has infinite span and creates a finite amount of lift. This one has an infinitesimally small angle of attack.
I think trinidefender is implicitly talkig about the first, while most others are implicitly talking about the second, am I correct? I hope this helps find common ground.

Coming from a completely different background: The law of conservation of energy demands that any wing, infinite span or not, that pushes air downwards, must pay a drag penalty. Here is where the wing with the infinitesimally small angle of attack can, in theory, get away with murder and zero drag (infinitesimally small, to be exact). Shoot me down if I am completely missig the point, please.

I just want to get off of the topic of wings with infinite wingspans as it has nothing to do with f1. PREVIOUSLY I was talking about a wing with infinite wingspan with a reasonable angle of attack. Either way can we please get back on topic.

We have established that on a finite wing not all of the induced drag comes from the creation of the wingtip vortex.

I'm going to try and ask others to do the same to refrain from posting things about infinite wingspans on this thread. Please......

[turbof1]

Agreed. I think we all more or less agree now anyway.

[NoDivergence]

Unless I haven´t followed correctly, you guys are talking about two different types of infinite span wings, with confusion arising from using the same name.
One type has infinite wingspan and a realistic angle of attack, and it produces an infinite amount of lift.
The second type has infinite span and creates a finite amount of lift. This one has an infinitesimally small angle of attack.
I think trinidefender is implicitly talkig about the first, while most others are implicitly talking about the second, am I correct? I hope this helps find common ground.

Coming from a completely different background: The law of conservation of energy demands that any wing, infinite span or not, that pushes air downwards, must pay a drag penalty. Here is where the wing with the infinitesimally small angle of attack can, in theory, get away with murder and zero drag (infinitesimally small, to be exact). Shoot me down if I am completely missig the point, please.

I just want to get off of the topic of wings with infinite wingspans as it has nothing to do with f1. PREVIOUSLY I was talking about a wing with infinite wingspan with a reasonable angle of attack. Either way can we please get back on topic.

We have established that on a finite wing not all of the induced drag comes from the creation of the wingtip vortex.

I'm going to try and ask others to do the same to refrain from posting things about infinite wingspans on this thread. Please......

More precise would be to say that the creation of the wingtip vortices affects the flowfield in between them and results in bounded vorticity between (horseshoe vortex). That's how you get the downwash distribution in between the wingtip vortices. With this downwash at any point y, you get alpha_induced at that location. With alpha_induced, you can find Drag_induced'.

Not all induced drag is in the wingtip vortices, but to get the right flowfield/w distribution, they need to be there.

[trinidefender]

I agree. Now let's relate this an F1 wing. Formula 1 has the unique situation where the low pressure side on rear wing wing is a closed loop. It is most similar to a closed loop wing. I'll find an article that I am currently working through on non-planar wing systems. The high pressure side has some restriction to span wise flow in the form of the endplates, endplate slots and on some teams wings, wing fences.

The wing is not considered infinite wingspan, just the formulas have to be changed slightly to encompass the fact that the low pressure side of the wing is a closed loop.

[NoDivergence]

I agree. Now let's relate this an F1 wing. Formula 1 has the unique situation where the low pressure side on rear wing wing is a closed loop. It is most similar to a closed loop wing. I'll find an article that I am currently working through on non-planar wing systems. The high pressure side has some restriction to span wise flow in the form of the endplates, endplate slots and on some teams wings, wing fences.

The wing is not considered infinite wingspan, just the formulas have to be changed slightly to encompass the fact that the low pressure side of the wing is a closed loop.

Correct, the presence of the endplates does significantly restrict this high pressure to low pressure flow migration, but it does not completely restrict it. In addition, with the presence of the DRS activation structure, there is a decent amount of spanwise flow, even for a low AR wing.

There are very defined experimentally found equations for the addition of endplates to performance of finite AR wings. These are typically for generic shapes, depending on who studied them.

It ranges from rectangular to elliptical endplates of differing AR. And yes, there are e values for closed wings (don't have my class notes on me, but i think it's something to do with Prandtl's wing box).

Unfortunately for F1, regulations prevent the endplate from rising much higher than the trailing edge of the last element.
McBeath has shown that that regulation loses some performance.

For some of the more complicated endplates of F1, I don't believe a singular equation can define the performance of the wing. These have heavy scalloping, and aren't constant geometry all the way down.

IMO, you need CFD/testing to evaluate a design on a case by case basis.

Remember, these wings are not fully closed in the sense of a wing box. Whatever is on the bottom of these wings varies depending on each teams suspension/diffuser/gearbox layout

There's a tradeoff here of reducing induced drag and increasing skin friction drag.

[trinidefender]

I like where this discussion is going now. I will continue to go through my papers on non planar wings to see what kind of numbers I can dig out for box wings as currently I see a box wing as being the closest thing we have to F1. I saw a few calculations being done on a box wing however in that example both the upper and lower side generated lift (or downforce in our case) on that wing. I'll see if I can get something similar only representing a box wing where only one side is producing lift.

Maybe the rear wing isn't as inefficient as was once touted, especially now with how the endplates have slots by the front tyre etc.

*edit* and I don't know why I didn't mention this before. On a conventional finite wing you have inward flow on the low pressure side and outward flow on the high pressure side. However if you look at pictures of F1 wings from behind while they are running flowvis paint you will notice that the bottom of the wing (low reassure side) has an outward flow direction as well. Even on wings that have the same camber line throughout their span.

Input of how this might affect things? Going to have to do even more reading now lol.

*edit No.2* maybe the mods can change the name of this thread to "Rear wing design/dynamics" instead? It was me who started this thread in the first place anyway.