A novel in-situ calibration method for acoustic particle velocity sensors based on surface velocity
The lack of standardized procedures for characterizing particle velocity sensors has triggered the development of novel calibration methods. Most current techniques use sound pressure measurements in combination with acoustic impedance models in order to estimate the particle velocity perceived at a given location. Measurements performed in a standing wave tube allow for accurate acquisition of both quantities but in a rather constrained frequency range. Alternatively, a full-bandwidth calibration method has also been proposed based on a two-step approach: high frequency calibration in free field conditions and low frequency calibration measuring sound pressure inside the source. Despite the accuracy of the latter method, it is fairly complex and has to be performed in a controlled environment. In this paper, a novel calibration method is introduced based upon surface velocity measurements of a moving, rigid enclosure while the sensor remains static. It is shown that the surface displacement of the cavity is directly related to the particle velocity perceived by the sensor providing the wavelength of the sound is far greater than the cavity dimensions. The foundations of this in-situ technique are introduced along with the experimental investigation of a prototype calibrator.
Fernandez Comesana, D., Tijs, E., Janszen, M. and Pousa, G.C., A NOVEL IN-SITU CALIBRATION METHOD FOR ACOUSTIC PARTICLE VELOCITY SENSORS BASED ON SURFACE VE-LOCITY. Proceedings of ICSV22.