摘要:

The radiation‐loading distribution over a large, rigid, circular piston embodies fluctuations associated with Freznel zone interference patterns. These fluctuations do not vanish as thekaof the piston tends to infinity, thus leading to the paradoxical conclusion that an infinite, rigid, plane piston does not radiate plane waves. It is shown that plane‐wave radiation and a uniform, ρcimpedance can be predicted by accounting for the transients occurring at the beginning of a CW pulse. These transients produce a ρcimpedance in regions of the piston not yet reached by a diffraction wave that starts from the piston edge at the beginning of the pulse. By allowing the piston diameter and, hence, the envelopment time to become arbitrarily large, the plane‐wave radiation loading prevails over an arbitrarily large region of the piston.

ISSN:0001-4966    

DOI:10.1121/1.1909842

出版商:Acoustical Society of America    

年代:1965

数据来源: AIP

ISSN:0001-4966    

DOI:10.1121/1.1909843

出版商:Acoustical Society of America    

年代:1965

数据来源: AIP

摘要:

The chemical analysis of sea water sampled in the Tongue of the Ocean is presented as a function of depth. Water temperature and sound velocity are also tabulated for each depth. The results are quite typical of the Caribbean, with the exception of somewhat larger percentages of bicarbonate and calcium ions.

ISSN:0001-4966    

DOI:10.1121/1.1909845

出版商:Acoustical Society of America    

年代:1965

数据来源: AIP

摘要:

A method has been devised for reducing the level of specific harmonics from underwater sound sources by introducing an out‐of‐phase harmonic signal at the electrical input to the system. Experimental results show that a significant reduction in harmonic level can be obtained by this method.

ISSN:0001-4966    

DOI:10.1121/1.1909847

出版商:Acoustical Society of America    

年代:1965

数据来源: AIP

摘要:

A pure‐tone “point” source of sound was placed within the potential core of a nitrogen jet at −180°C, and the distortion of its sound field by the jet temperature and velocity fields was measured. The sound was found to be refracted inward—a focusing effect—to yield a maximum intensity along the jet axis; the maximum increased with frequency and decreased with jet velocity. Polar directional plots of the self‐noise of the cold jet (“jet noise”) exhibited a similar shape, quite unlike the usual heart‐shaped pattern for warmer jets.

ISSN:0001-4966    

DOI:10.1121/1.1909848

出版商:Acoustical Society of America    

年代:1965

数据来源: AIP

ISSN:0001-4966    

DOI:10.1121/1.1909849

出版商:Acoustical Society of America    

年代:1965

数据来源: AIP