Predicting the behaviour of a closed circular airfoil

Click For Summary

Discussion Overview

The discussion revolves around the behavior of a closed circular airfoil, particularly in the context of its lift and drag properties when projected through the air. Participants explore theoretical predictions and the physics behind a large-scale version of this concept, comparing it to existing airfoil designs.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant observes the flight of a frisbee and speculates on the airflow and forces acting on a closed-loop airfoil, questioning its potential flight behavior without computational fluid dynamics (CFD) software.
  • Another participant provides links to examples of similar concepts, such as the Flying Gyroscope and Aerobie, suggesting these may relate to the original idea.
  • A participant expresses interest in the physics of a larger, 30m diameter airfoil, noting that while similar designs exist, they seek specific research or papers on the topic.
  • Discussion includes the consideration of a doughnut-shaped wing, with one participant noting it may weigh more than flattened designs for the same lift and require larger hangar space.
  • Another participant requests comprehensive explanations and predictions about the behavior of a doughnut-shaped airfoil, acknowledging practical limitations in building such a model.
  • A suggestion is made regarding the availability of free software for testing airfoil designs and the possibility of using a small-scale wind tunnel for experimentation.
  • A participant confirms they have found free CFD software to explore their ideas further.

Areas of Agreement / Disagreement

Participants express varying levels of interest and knowledge about the topic, with some seeking theoretical predictions while others provide resources or suggest practical experimentation methods. No consensus is reached on the specific behavior of the proposed airfoil designs.

Contextual Notes

Participants acknowledge limitations in practical experimentation and the availability of resources for testing their ideas. There is also a recognition of the complexity involved in predicting the behavior of large-scale airfoils.

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.
 
Last edited by a moderator:
Engineering news on Phys.org
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.
 
Thanks for that.

What about a 30m doughnut-shaped wing?
 
Limacharlie said:
What about a 30m doughnut-shaped wing?
Weights more then "flattened" closed wing designs (for same lift) and needs a bigger hangar.
 
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 >>
 
Last edited by a moderator:
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? :smile:
 
Hi,

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

Thanks
 
  • Like
Likes   Reactions: berkeman

Similar threads

Mathematica Aerodynamics: Mathematically Modeling the Flight of an Object
  • · Replies 11 ·
Replies
11
Views
10K
Mathematica This Week's Finds in Mathematical Physics (Week 264)
  • · Replies 6 ·
Replies
6
Views
5K
Mathematica This Week's Finds in Mathematical Physics (Week 266)
  • · Replies 1 ·
Replies
1
Views
4K
Mathematica This Week's Finds in Mathematical Physics (Week 257)
  • · Replies 5 ·
Replies
5
Views
5K