A time reversal procedure used previously for aeroacoustic source localization is extended to the viscous flows case. Successive flow configurations including steady flows and unsteady ones have been performed to test and validate the proposed procedure. It is demonstrated that it provides a useful methodology for the detection and the localization of aeroacoustic sources, not only in presence of a dissipative medium but also in unsteady flow configurations. When dealing with dissipative media, the application of time-reversal procedure allows for the recovery of both the shape and the location of the source of sound even if the source amplitude is damped due to the viscous energy loss. For unsteady flows (in presence or not of a dissipative medium), the aeroacoustic source detection method remains always effective even if some theoretical assumptions are not fully satisfied.