The aeroacoustic field generated by a transonic two-blade Hartzell propeller was calculated by using Kirchhoff method.The Kirchhoff surface was defined as a nonrotating cylinder surrounding the whole propeller blade.The aerodynamic flowfield was firstly computed by using the Flower code running in the Euler mode

then the farfield acoustic pressure was calculated with the Kirchhoff method.A detailed numerical study revealed the influence of the radius and height of the cylinder on the acoustic pressure in the farfield.The results obtained by the Farassat's linear method were also presented and compared with the presented results.The comparison of the results obtained by both the methods with experimental data demonstrated that the Kirchhoff method considering most of the nonlinear effects gave a better results than the linear method.