Meseauring torque-energy in a sheet of material (air)

Hello @molen_victor , that sounds a bit tricky.

What I would like to understand is that how can you directly relate air speed vs thrust coefficient without putting any geometrical information? Do you have some sort of empirical formula for a specific rotating device that presents a graph, or something else?

I think, rather than looking at velocity contours, creating probe points and obtaining velocity magnitudes should be more helpful.