Detection of fluid velocity and hydroacoustic particle velocity using a temperature autostabilized nonlinear dielectric element (TANDEL)

Abstract

A ferroelectric sensor operated in the temperature autostabilized mode was developed for the measurement of the particle motion in hydroacoustic fields. The sensor is a capacitorlike element constructed from antimony sulfur iodide (SbSI) single crystals and SbSI–polymer composites. The device is operated slightly above the Curie point of SbSI, which is approximately 20 °C. Using a Schering bridge, the element is heated by driving it through the hysteresis cycle. The heat transferred to the surrounding fluid is related to the motion of the fluid. The technique was applied to the measurement of a constant velocity flow field and to a low-frequency acoustic field. In the case of the constant velocity flow field, an exponential relationship between fluid velocity and sensor voltage was observed. For acoustic fields, the response of the sensor decreased sharply with frequency above 100 Hz. The acoustic particle velocity could be measured to a frequency around 1 kHz.