Computation of acoustic power, vibration response and acoustic pressures of fluid-filled pipes

Acoustic power radiated into the fluid around a pipe subjected to time harmonic excitation, the vibration response of the pipe wall, and the pressures in the exterior and interior fluids are computed. Pressure fields and pipe displacements are represented by Fourier transformations, and the acoustic power in the surrounding fluid is obtained from the stationary phase approximation to the far field pressure. The integral representations of fluid pressures, pipe displacements and radiated power are evaluated by a simple numerical quadrature scheme. Decibel level versus frequency plots for the responses in the individual circumferential harmonics of a water filled steel pipe surrounded by air are presented.