Predicting the behaviour of a closed circular airfoil

[Limacharlie]

I was out and about today and observed a dog walker playing frisbee with their dog. I noticed the frisbee gliding gracefully through the air as the dog jumped to grab it, clutching the ring-like disc in its mouth.

It got me to thinking about airflow over the disc, the lift and drag properties of the shape and what would make it fly longer. Which then lead me to imagine what would happen if the disc was to be turned on its side and somehow projected through the air. Obviously, a flat disc such as a frisbee would drop immediately in front of you, caused by too much drag. But, what if the disc was produced to be an airfoil shape, such as a wind turbine blade or a wing of an aircraft? I mean literally taken one of these and bending it around an enormous jig and joining the ends, then making it uniform all of the ways around. Then somehow firing this giant ring into the air on an arc.

Because the shape of an airfoil creates lift in the upward direction, my intuition tells me that the forces would balance out and in theory would fly for x amount of time with friction and gravity acting on it.

Could anyone predict the behaviour of my closed-loop-airfoil on a large scale without CFD software?

And what would the forces be doing acting on it?

Thanks, everybody.

 

[A.T.]

such as a wind turbine blade or a wing of an aircraft? I mean literally taken one of these and bending it around an enormous jig and joining the ends

You mean like this?

https://en.wikipedia.org/wiki/Flying_gyroscope



Or like this?

https://en.wikipedia.org/wiki/Aerobie

 

[Limacharlie]

Yes like the X-zylo.

But I'm interested in the physics of a larger, upscaled one like 30m in diameter.

I understand it has been done before but couldn't find anything on the internet that satisfies my question. I'm sure there's a ton of research done on this topic in the aerospace industry, do you have any links to theses or papers, perhaps

Thanks anyway, appreciate it.

 

[A.T.]

But I'm interested in the physics of a larger, upscaled one like 30m in diameter.

https://en.wikipedia.org/wiki/Closed_wing

 

[Limacharlie]

Thanks for that.

What about a 30m doughnut-shaped wing?

 

[A.T.]

What about a 30m doughnut-shaped wing?

Weights more then "flattened" closed wing designs (for same lift) and needs a bigger hangar.

 

[Limacharlie]

OK, I appreciate you taking the time to try and answer my question and provide me with links.

Maybe I wasn't clear enough in my question, I was hoping to get some comprehensive explanations and predictions and maybe model some of the behaviours of what a doughnut-shaped airfoil would do. Obviously, building one in real life is either pointless or not cost effective. And obviously, there are no hangars to support this.

<< Mentor Note -- post edited >>

 

[berkeman]

I don't know much about Aero, but are there free software packages that let you try out different airfoil designs to see how they do? Or maybe there is a small scale wind tunnel near you that you could get some time in with some models for you to try out your ideas?

 

[Limacharlie]

Hi,

Yes, I've found some free CFD software which I'm downloading as we speak.

Thanks