Thermal Interference When Recording Turbulent Pressure Fluctuations on the Surface of a Floating Device

Abstract

Thermal interference is studied when recording turbulent pressure fluctuations on the surface of a floating device at specified experimental parameters of temperature stratification of an aquatic medium. The effect of distortion of the spectral levels of pressure fluctuations recorded by a sound receiver in the field of temperature inhomogeneities is studied using the example of measurements of turbulent pressure fluctuations in the boundary layer during the vertical ascent of a device from a specified depth. At moderate flow velocities exceeding 1–2 m/s, the temperature susceptibility of a piezoceramic receiver is shown to be decisively determined by its characteristic “thermal” frequency. The parameters of the threshold critical frequency, below which the temperature signal (thermal interference) prevails over the useful signal generated by pressure fluctuations, are determined. With respect to the receivers used in experiments on a floating device [7], the values of the threshold critical frequency are 130 and 215 Hz.