摘要:

An operational method is proposed for evaluating integral equations that are often encountered in the solutions for the farfield radiation from plane boundaries. This method leads to results that are similar to those obtained by the method of steepest descent.

ISSN:0001-4966    

DOI:10.1121/1.1911501

出版商:Acoustical Society of America    

年代:1969

数据来源: AIP

摘要:

Various choices for the boundary condition on a piston radiating from a nonrigid battle are discussed.

ISSN:0001-4966    

DOI:10.1121/1.1911503

出版商:Acoustical Society of America    

年代:1969

数据来源: AIP

摘要:

The three lowest natural frequencies of transverse vibration are derived for a long hanging chain, the upper end of which is fixed and the lower portion is confined. The method by which the natural frequencies are obtained, is described and mode shapes are given.

ISSN:0001-4966    

DOI:10.1121/1.1911505

出版商:Acoustical Society of America    

年代:1969

数据来源: AIP

摘要:

A thin elastic rod is clamped between two rigid plates. The governing partial differential equation is nonlinear owing to the presence of Coulomb friction, which acts at the surfaces of contact. The displacement, velocity, and strain may be solved for when a stress pulse is applied for particular time periods. The stress wave penetrates the rod to a depth which depends on the applied stress and the friction force. When the motion of the rod is entirely damped out by the friction, a residual stress distribution remains.

ISSN:0001-4966    

DOI:10.1121/1.1911507

出版商:Acoustical Society of America    

年代:1969

数据来源: AIP

摘要:

Long period variations of sound speed at 560 m depth in the Sargasso Sea show correlations with to‐and‐fro movements of a ship 39 miles away that was keeping station during acoustical measurements. The results suggested that long‐crested internal gravity waves may be responsible.

ISSN:0001-4966    

DOI:10.1121/1.1911509

出版商:Acoustical Society of America    

年代:1969

数据来源: AIP

摘要:

The preponderance of recent determinations of distilled‐water sound speed indicates that the Wilson (for the range 0°–30°C) and Greenspan‐Tschiegg sound‐speed equations are too high by 65 and 40 cm/sec, respectively. Similarly, the Wilson seawater sound‐speed equation gives Pacific temperate latitude Sofar speeds23 m/sechigher than values based on explosion travel times. Adjusted distilled and seawater equations are proposed in order to achieve a common standard for all measurements at sea.

ISSN:0001-4966    

DOI:10.1121/1.1911511

出版商:Acoustical Society of America    

年代:1969

数据来源: AIP

摘要:

Spectrum broadening, caused by ocean‐wave interface, is explained in terms of an equivalent fluctuating dipole arm.

ISSN:0001-4966    

DOI:10.1121/1.1911513

出版商:Acoustical Society of America    

年代:1969

数据来源: AIP

摘要:

In a previous Letter [M. Schulkin, J. Acoust. Soc. Amer.44, 1152(L), (1968)], an empirical relation was presented for wind‐speed controlled losses in ocean‐surface duct propagation. which holds over a wide range of frequencies (1.5 to 25 kHz) and waveheights. This relation isas= 1.64 (fh)1/2 dB limiting ray cycle, wherefis the acoustic frequency in kilohertz andhis the mean crest‐to‐trough waveheight in feet. In this Letter, evidence is presented that this behavior can result front the combined effect of (1) bubble‐density distribution with a tail that falls off approximately asR−7.2, whereRis the bubble radius; (2) bubble‐volume concentration decaying with depthzapproximately as a ɜ−1.2modified by a small dependence on layer depth and hydrostatic pressure; and (3) bubbles that mostly originate from breaking wind waves.

ISSN:0001-4966    

DOI:10.1121/1.1911515

出版商:Acoustical Society of America    

年代:1969

数据来源: AIP

摘要:

Detection of a signal of known shape in white Gaussian noise of unknown spectral density can be accomplished with the same error probabilities as when the spectral density of the noise is known.

ISSN:0001-4966    

DOI:10.1121/1.1911517

出版商:Acoustical Society of America    

年代:1969

数据来源: AIP

摘要:

Some points in the original paper are reiterated and emphasized.

ISSN:0001-4966    

DOI:10.1121/1.1911519

出版商:Acoustical Society of America    

年代:1969

数据来源: AIP