Validation of supersonic intensity in reverberant environments (SIRE) with respect to underwater acoustic sources

摘要

Supersonic Intensity in Reverberant Environments (SIRE) is validated numerically andexperimentally. The SIRE technique permits the measurement of narrowband radiatedsound power and directivity in an environment with unknown field conditions.Underwater acoustic intensity vector sensors are used in the near field of a source allowingthe outgoing acoustic waves to be separated from incoming acoustic waves. Supersonicwavenumber filtering rejects the evanescent waves from the outward-propagating soundpressure and particle velocity. SIRE is applied to a monopole and a dipole. The results arecompared with theory and the ANSI S12.51 standard one-third-octave reverberation roommethod. SIRE is shown to accurately measure radiated sound power within the limits ofANSI S12.51 and directivity indices of simple sources to within ±3 dB. Finally, a coupledfinite element/boundary element (FE-BE) model of a point-driven, thin-walled cylinder in areverberant water tank is developed. The results show that the measurement standoffdistance for the SIRE technique should be less than the reciprocal of the largestwavenumber of interest. Furthermore, the maximum measurement grid spacing should beless than twice the standoff distance.