A note on a solution of Possio’s integral equation for an oscillating airfoil in subsonic flow

Following a procedure analogous to that used by Schwarz for solving the integral equation for an oscillating airfoil in incompressible flow, a method of attack on the same problem for subsonic, compressible flow is outlined. The circulation and kernel to the circulation integral equations are expanded in series with the coefficients ${M^{2n}}$ and ${M^{2n}}$ ln $M$, and a corresponding expansion for the Green’s function is thereby implicitly determined. The solution up to (but not including) terms of $O\left ( {{M^4},{M^4}\ln M} \right )$ is stated. A method of iteration for improving a given solution is also indicated.