摘要:

Several different hypotheses have been proposed in the literature to explain the physical mechanism whereby transverse vibrations increase the rate of heat transfer by free convection from horizontal cylinders. The present paper contains a discussion of the validity of these hypotheses in the light of recent experimental data.

ISSN:0001-4966    

DOI:10.1121/1.1909146

出版商:Acoustical Society of America    

年代:1962

数据来源: AIP

摘要:

An asymptotic solution of the frequency equation of an infinite, monoclinic crystal plate is derived. Formulas are given which describe the variation of frequency with wavelength at high frequencies and long wavelengths.

ISSN:0001-4966    

DOI:10.1121/1.1909147

出版商:Acoustical Society of America    

年代:1962

数据来源: AIP

摘要:

A sketch is constructed of the branches of Ekstein's frequency equation for an infinite, monoclinic crystal plate. The sketch is for the AT cut of quartz and covers a wide range of frequencies and propagation constants. The real, imaginary, and complex segments of the branches are included.

ISSN:0001-4966    

DOI:10.1121/1.1909148

出版商:Acoustical Society of America    

年代:1962

数据来源: AIP

摘要:

A general solution is given for the contour modes of vibration of circular crystal disks of certain elastic symmetries. The solution is applicable to three cuts of quartz, for which the frequencies of fourteen modes are computed.

ISSN:0001-4966    

DOI:10.1121/1.1909150

出版商:Acoustical Society of America    

年代:1962

数据来源: AIP

摘要:

Pressure waves, generated different points along radial runs on the continental shelf and slope south of Long Island by 1‐1b explosions of TNT, were received by hydrophones connected by sea cables to a fixed station in the ocean. An extensive analysis of the dispersion phenomenon in the water wave covering five radial courses within a 150‐mile radius of the receiving station was made. Nearly 500 charges were examined in this analysis, and the “seasonal” effect upon dispersion was investigated. In general, for shallow water the received pressure wave displays certain features that are characteristic of the depth of the water, the velocity‐depth contour in the water, the range, and the structure of the bottom. Dispersion in the water wave was also observed in a surface channel formed in moderately deep water. The observed dispersion phenomena were studied quantitatively, and the data were interpreted in terms of the bottom structure. Two‐ and three‐layer liquid models were employed to interpret the experimental results. An expression is presented that relates all the parameters pertinent to the dispersion phenomenon.

ISSN:0001-4966    

DOI:10.1121/1.1909151

出版商:Acoustical Society of America    

年代:1962

数据来源: AIP

摘要:

The effect of phase fluctuations on the mean‐square time‐averaged output of a discrete linear array is considered under the assumption that the fluctuations are governed by a Gaussian joint‐probability density function. In particular, a closed‐form expression is derived for the variance of the array output over the ensemble of phase variations.

ISSN:0001-4966    

DOI:10.1121/1.1909152

出版商:Acoustical Society of America    

年代:1962

数据来源: AIP

摘要:

A theoretical analysis given of the scattering of plane acoustic waves by a thin‐walled metallic cylinder in water. It is shown that a surface wave of low attenuation is propagated around the cylinder as a flexural vibration and that this wave acts as the “creeping” wave discussed by Franz. The phase velocity of this wave depends on frequency so that one must use group velocity for short pulses. Theoretical calculations are compared with experimental measurements made on an aluminum and a brass cylinder of wall thickness 0.094 in. and o.d. 5.475 in. over a frequency range of 70 to 130 kc/sec. The theoretical curve of the velocity of pulses around the aluminum cylinder shows a frequency dependence that agrees with the experimental curve, but the magnitude of the theoretical value of the velocity is 10% too low. It is not possible to excite these waves in the brass cylinder with the present experimental arrangement.

ISSN:0001-4966    

DOI:10.1121/1.1909153

出版商:Acoustical Society of America    

年代:1962

数据来源: AIP

摘要:

The power‐handling capabilities of ceramic piezoelectric transducers in pulsed operation at low duty rate are limited by tensile rupture. Compressive bias has been used to increase the power‐handling capabilities of integral spheres; this mechanical bias has been applied by controlled nickel electroplating over the outer surface, such that the plated coating is under high tensile stress. Units formerly limited to 50 W/cm2can now be operated at 200 W/cm3.

ISSN:0001-4966    

DOI:10.1121/1.1909154

出版商:Acoustical Society of America    

年代:1962

数据来源: AIP

摘要:

The results of recent ambient‐noise investigations, after appropriate processing, are compared on the basis of pressure spectra in the frequency band 1 cps to 20 kc. Several possible sources are discussed to determine the most probable origin of the observed noise. It is concluded that, in general, the ambient noise is a composite of at least three overlapping components:turbulent‐pressure fluctuationseffective in the band 1 cps to 100 cps; wind‐dependentnoise from bubbles and sprayresulting, primarily, from surface agitation, 50 cps to 20 kc; and, in many areas,oceanic traffic, 10 cps to 1000 cps. Spectrum characteristics of each component and of the composite are shown. Additional sources, including those of intermittent and local effects, are also discussed. Guidelines for the estimation of noise levels are given.

ISSN:0001-4966    

DOI:10.1121/1.1909155

出版商:Acoustical Society of America    

年代:1962

数据来源: AIP

摘要:

Computed curves of the dimensionless phase velocity (c/cL) of plane longitudinal waves in infinite plates for values of the parameter ν (Poisson's ratio) from 0.25 to 0.40 are presented.

ISSN:0001-4966    

DOI:10.1121/1.1909158

出版商:Acoustical Society of America    

年代:1962

数据来源: AIP