This article presents a comparative analysis of the influence of different types of flows over fan noise propagation and scattering within the nacelle intake of aircraft turbofan engines. The methodology for the noise simulation is explained. First, the fan noise source is modeled using a boundary condition that represents all the uncorrelated cut-on modes in the interior of the nacelle duct. Then different types of flows and flight conditions are considered in order to determine the influence of the aerodynamic phenomenon in the noise emitted by the nacelle intake. The liner attenuation is also simulated by mean of Myers boundary condition. Finally the results for far field noise are validated against numerical data obtained from the literature for hard and lined wall conditions.