Browsing CMRE Publications by Subject "Underwater acoustics"
Now showing items 61-73 of 73
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Summary and recommendations
(NATO. SACLANTCEN, 1971/12)An unfortunate first impression might be that ray tracing is dull, simply because the idea is a very old one. In fact, ray tracing is the single most powerful method available to us for understanding the complexities of ... -
The effect of gravity-forced oscillations at the base of the duct on its effective depth as a channel for acoustic rays
(NATO. SACLANTCEN, 1971/12) -
The influence of a low velocity layer on the reflectivity from the sea floor
(NATO. SACLANTCEN, 1966/05)The influence on the reflectivity of a low velocity layer on top of a sand half-space has been investigated. By expressing sediment density and velocity in terms of porosity it has been possible to use this quantity as an ... -
The optimum frequency of propagation in shallow-water environments
(NATO. SACLANTCEN, 1983/04)The optimum frequency of propagation in shallow water environments is the result of competing propagation and attenuation mechanisms at high and low frequencies. It is shown that the optimum frequency is strongly dependent ... -
The reverberation of sound from smooth ocean floors
(NATO. SACLANTCEN, 1963/02)The reverberations produced by a completely flat surface separating two homogeneous isotropic fluids is investigated. There is no effort to include the effect of rough surfaces which would be a logical extension of the ... -
The sea surface as a random filter for underwater sound waves
(NATO. SACLANTCEN, 1974/06)In this dissertation the phenomenon of scattering and reflection of underwater sound waves from the sea surface is studied by considering the surface sound channel as a random, time-dependent filter. This filter can be ... -
The wave equation in a medium with a time-dependent boundary
(NATO. SACLANTCEN, 1974/02)It is shown that the Helmholtz equation is not exactly correct for a medium with a time-dependent boundary. The equation can be used with very good approximation when the time-derivative of the surface elevation is much ... -
Theoretical calculation of transmission loss in the ocean
(NATO. SACLANTCEN, 1971/12)The topic that is dealt with in this paper is a method for c omputation of acoustic transmission loss by sound propagation in the ocean. The method i s based on the ray theory which is used in connection with an acoustic ... -
Toward the development of secure underwater acoustic networks
(CMRE, 2019/05)Underwater acoustic networks (UANs) have been recognized as an enabling technology for various applications in the maritime domain. The wireless nature of the acoustic medium makes UANs vulnerable to various malicious ... -
Underwater acoustics - modelling: keynote address
(NATO. SACLANTCEN, 1975/10) -
Underwater ambient noise: proceedings of a conference held at SACLANTCEN on 11-14 May 1982, vol. 2 - Unclassified Papers, part 2
(NATO. SACLANTCEN, 1982/06)Contents: PROCESSING TECHNIQUES--A method of estimating the influence of ship's noise on ambient noise measurements; Optimal detection and tracking of acoustical noise sources in a time-varying environment; Influence of ...