Challenges in Implementing McCormic's Vortex Theory of Propellers

[Antonio9393]

Hello all,

I have been attempting to perform the iterative procedure outlined in McCormic's textbook (1995) for the vortex theory of propellers. However, I have become stumped when attempting to get tangential velocity relative to tip speed after the first iteration as a part of the equation is the sqrt of an expresión times x - wt/vt where x is relative radial position. When getting close to the hub, x becomes too small, and I get an imaginary number. Does anyone have any useful thoughts? I will attempt to start the program from scratch again tomorrow

 

[Baluncore]

I do not have a copy of that textbook and am not sure exactly which version of vortex theory you are using, but the propeller has a hub where it attaches to the shaft. You should not need to compute inside the hub and shaft. As you approach the shaft axis the tangential velocity falls to zero while the axial traveling velocity remains. I do not know the orientation of your coordinate system so I cannot go further than that.

 

[Antonio9393]

Think you very much for your help. Eliminating the relativa radial positions of the blade that ranged from 0 to 0.1 makes sense. Your explanation on the tangential and axial components of the resultant flow also was of great help as it helped me understand the expected results. I'll keep you posted on my progess but already the program is running much smoother