David Van Tol
W. Jack Hughes
Appl. Res. Lab., Penn State Univ., P.O. Box 30, State College, PA 16804
The desired characteristics and properties of an underwater intensity probe are best achieved by constructing the sensor out of the polymer polyvinylidene fluoride (PVDF), which has the properties of high sensitivity, small thickness, and an impedance close to that of water. An array is being designed to measure the acoustic intensity in two dimensions and at several collinear points. Since the characteristic impedance of PVDF is close to that of water, the PVDF sensors are almost acoustically transparent. This helps to minimize the scattering and interference caused by the probe. The probe array is designed for use over a frequency range of 500 Hz to 5 kHz. Design data will be presented, and calibration measurements of magnitude and phase will show how well the probe performed. Some of the advantages, disadvantages, and construction problems with PVDF sensors will also be addressed.