In this work a procedure for the aero-acoustic characterization of air jets was presented. The ability of a laser vibrometer to assess the changes in the optical path induced by local fluctuation of air refraction index was used to calculate the pressure oscillations produced by turbulence. The signal from the laser must be treated in order to extract the required information. From the pseudo velocity, which represents the integral of the refraction index distribution along the laser beam, it is possible to calculate, by a tomographic algorithm, the volumetric distribution of the refraction index at each frequency, and then the pressure oscillation. Each pressure voxel represents a sound source, i.e. monopole, that gives contribution to the Sound Pressure Level in each point of the surrounding. The uncertainty of the procedure was also evaluated.
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