[aerhohead]

Hello All, I am trying to write up a quadratic strength doublet-vortex panel method to then implement an adjoint optimization method for shape optimization. I am starting off with a basic constant strength vortex panel method to crawl before I fly. I have been having terrible failures in writing the basic constant strength vortex panel method. I have quadruple checked my calculations and can't seem to find the issue. My vortex strengths, tangential velocity, and Cp plots show high numerical error especially due to unstable oscillations. I have attempted writing the code using a local flat panel reference frame, and then from a regular global reference frame. I would really appreciate any help or guidance that you can provide.

attached are my codes for the NACA 4 series airfoil function, vortex panel function, and 2D panel geometry functions.