Low frequency responses of spherical and cylindrical pressure-gradient hydrophones due to adjacent turbulent pressure fluctuations

Low frequency responses of both spherical and cylindrical pressure gradient hydrophones with different sizes are analyzed under the assumption that the adjacent turbulent pressure fluctuations are a substantial contributor to the acoustic ambient-noise level for low frequencies. This study demonstrates the predicted equivalent sound pressure level at low frequencies can be reduced by changing the shape and/or the size of the pressure gradient hydrophone. The equivalent sound pressure levels of both spherical and cylindrical shapes of the same diameter at very low frequencies (0.01Hz to 0.5Hz) are the same. As the frequencies increase the equivalent sound pressure level of the spherical hydrophone decreases faster than that of the cylindrical one.