[N382] Acoustic Source Localization based on Pressure and Particle Velocity Measurements

Inverse source identification techniques are used to find the acoustic sources on the surface of a sound radiating object. One of the most general applicable methods is the inverse frequency response function method (IFRF). The standard IFRF technique uses acoustic pressure measurements performed on a measurement grid in the nearfield of an acoustic source to determine the corresponding normal velocities on the surface of the source. To relate the measured field pressures to the surface vibrations, a transfer matrix is calculated with a boundary element solver (BEMSYS). In the source localization process, this matrix needs to be inverted in order to predict the original surface normal velocities. Generally, the transfer matrix is ill-conditioned and can only be solved by applying regularization techniques. In this paper, apart from conventional pressure measurements, it is investigated whether the nearfield particle velocities, measured with a Microflown sensor, can be used to reconstruct the original source vibrations. By means of an experimental setup, a comparison is made between pressure based and velocity based IFRF.