Accession Number : AD0784334

Title :   Investigation of the Increase in Parametric Efficiency Due on Bubbles.

Descriptive Note : Technical rept.,

Corporate Author : AMETEK EL CAJON CALIF STRAZA DIV

Personal Author(s) : Lockwood,J. C.

Report Date : 30 AUG 1974

Pagination or Media Count : 79

Abstract : A demonstration of the increase in parametric array efficiency due to bubbles produced by forcing air through a microporous filter is reported. With the introduction of bubbles, an increase of 30 dB in the sound pressure level at a secondary frequency of 10 kHz was measured at a range of 1.83 m. The mean primary frequency was 50 kHz. Results extrapolated to the far-field of the parametric array indicate that the increase in sound pressure level at a distant point would have been only 16 dB. The disparity between the gains at near and far points is the result of the incomplete generation of the secondary signal at the near point. (Modified author abstract)

Descriptors :   *Sonar arrays, *Sonar signals, *Bubbles, Acoustic beams, Near field, Performance

Subject Categories : Acoustic Detection and Detectors

Distribution Statement : APPROVED FOR PUBLIC RELEASE