Crowsnest

Lifting flow around a circular cylinder

Hello Crowsnest. You produced the excellent diagram with the caption “Streamlines for the incompressible potential flow around a circular cylinder in a uniform onflow.” It is available at Potential flow#Description and characteristics. It shows flow with circulation of zero.

There is a need for a similar diagram but with a non-zero circulation. Such a diagram could be applied at Magnus effect and Kutta–Joukowski theorem. The symmetry of the streamlines about a vertical axis through the centre of the cylinder would be helpful in demonstrating that in two-dimensional flow the upwash upstream of a cylinder is a mirror image of the downwash downstream of the cylinder. It would also help demonstrate that there is no lift-induced drag in two-dimensional flow about an airfoil.

The diagram I have in mind is often used in text books and websites. For example, the one by Prof Richard Fitzpatrick (University of Texas) shown at the following website:

Flow Past a Cylindrical Obstacle

Are you able to produce such a diagram for use on Wikipedia? Dolphin (t) 12:35, 30 March 2024 (UTC)

Dear Dolphin51, hope you are doing well. Thank you very much for the interest. Yes, I agree that the difference in symmetry about a horizontal and vertical axis can be of help to explain the existence of lift without drag. I will have to try to find the code and adapt it. I will keep you informed on the progress. Kind regards, Crowsnest (talk) 20:55, 2 April 2024 (UTC)

Thank you. Dolphin (t) 22:09, 2 April 2024 (UTC)

I made a similar request at User Talk:Thierry Dugnolle#Potential flow around a circular cylinder with circulation. I’m not confident Thierry will still be able to do animations on this subject. Dolphin (t) 22:23, 2 April 2024 (UTC)