How to convert magnus effect from 2d to 3d?

Click For Summary

Discussion Overview

The discussion revolves around the conversion of the Magnus effect from a two-dimensional to a three-dimensional context, particularly in relation to simulating the lift on a spinning ball. Participants explore the mathematical and conceptual challenges involved in this transition, including the application of spin in multiple axes and the interpretation of relevant physical directions.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant inquires whether the calculations for the Magnus effect on the x and y coordinates can be similarly applied when adding spin on the x-axis, suggesting a method for extending the 2D calculations to 3D.
  • Another participant suggests expressing the results in a coordinate-independent form, emphasizing the importance of using physically defined directions rather than arbitrary axes.
  • A participant references an article that discusses the Magnus effect in 3D space but expresses difficulty in understanding how to implement the concepts in their own code.
  • There is a mention of the article setting up equations of motion and producing solutions through perturbation techniques, indicating a more complex approach than initially considered.
  • One participant expresses uncertainty about the axes and unit vectors presented in a figure from the referenced article, questioning their relevance and clarity.
  • Concerns are raised regarding the absence of mass in the force equations provided in the article, which adds to the confusion about the implementation of the 3D model.

Areas of Agreement / Disagreement

Participants do not appear to reach a consensus on the best approach to transition from 2D to 3D modeling of the Magnus effect. There are multiple viewpoints on how to interpret the physical directions and the mathematical formulations involved.

Contextual Notes

Limitations include potential misunderstandings of the physical directions defined by the system, the complexity of the numerical modeling required for the 3D problem, and the unclear presentation of variables in the referenced article.

icandothemath
Messages
9
Reaction score
0
I am working on simulating the magnus effect of lift on a spinning ball. Right now spinning on the z axis I can calculate the force effect it has on the x and y coordinates.

If I am to add spin on the x do I do the exact same calculations effecting the y and z coords and just add them to the z spin forces?

And again do the same with the y spin effect on the x and z coords?

Thanks
 
Last edited:
Physics news on Phys.org
Express the answer you have obtained in coordinate independent form. To do this, interrogate the system by asking what directions does the system itself define. The axes x, y, and z were introduced by you and are not really relevant to the physical system. On the other hand, the unit vector in the direction of the local velocity and in the direction of the spin axis are physically defined directions. Try expressing your result in terms of these.
 
  • Like
Likes   Reactions: icandothemath
Thanks for the reply MarcusAqgrippa. I ended up stumbling upon this article that explains the effect in 3D space. http://www.crm.cat/en/publications/publications/2013/pr1154.pdf I do not totally understand it though. My implementation of the 2D effect can be found here http://forum.unity3d.com/threads/ho...-to-the-3d-world-sample-code-included.321682/ Now I just need a bit of help taking the 3D article and understanding the difference between my 2D model and how to implement that in source code.
 
That is a very nice article. In the theory it does what I suggested that you do, and more: it sets up the equations of motion and produces a solution by perturbation techniques.

You did not say initially that you were trying to construct a numerical model for the 3-d problem. That is a lengthy piece of work, and is not something that I have time to do. If you have well formulated questions, I may be able to assist you in answering them. But I think you may be asking for more.

Perhaps someone else with more time on their hands can assist you. It would nevertheless be useful were you to formulate your current difficulty a little more precisely. Your open ended plea for help may not attract many responses.
 
Ok, maybe as I go through that document I can ask for some help if that is ok?
In figure 1 of the pdf document. It talks about unit vector l, v, and v x l. Then spin rates around these axis.
I am unsure what these axis are. The arrows in figure 1 do not make sense to me.
They look like like point arbitrarily in directions. Except for v which looks to line up with the x axis.

Also in the Force equations below it says m is mass but there is no m in the formulas.
 
Last edited:

Similar threads

  • · Replies 25 ·
Replies
25
Views
4K
  • · Replies 9 ·
Replies
9
Views
4K
  • · Replies 7 ·
Replies
7
Views
30K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 4 ·
Replies
4
Views
7K
  • · Replies 1 ·
Replies
1
Views
3K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 8 ·
Replies
8
Views
2K
  • · Replies 2 ·
Replies
2
Views
1K
  • · Replies 60 ·
3
Replies
60
Views
7K