Ultrasonic field measurement in test cells combining the acousto-optic effect, laser interferometry and tomography

This paper describes a non-invasive measurement technique for the characterisation of acoustic fields generated by a commercially available 33 kHz Tonpilz transducer in fluid loaded cylindrical test cells. Firstly, a harmonic field prediction model was used to verify the experimentally measured pressure fields at various distances from the device front face under free field conditions. Next, the finite element code PZFlex was employed for the prediction of pressure field within cylindrical cell configurations. Finally, precise manipulation of the laser firing angle and position was implemented in order to compensate for the breakdown of the reconstruction procedure due to refraction at the cell walls. Results demonstrate reasonable correlation with the PZFlex predictions.