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Interference structure of the sound field of a wideband source in a model layered waveguide
OLR (1985)32 (9)
A. PhysicalOceanography
A260. Acoustics 85:4984 Ageeva, N.S. and V.D. Krupin, 1984. Behavior of the mode frequency responses in shallow water with variation of the longitudinal wave velocity in the bottom sediment layer and the sound-velocity profile in the water layer. Soy. Phys. Acoust. (a translation of Akust. Zh.), 30(5):341-345. N.N. Andreev Acoustics Inst., Acad. of Sci., USSR.
733
dependence on frequency and distance, are cornpc.red with a theoretical model to describe the spatial-frequency distribution in an acoustic waveguide. Inst. of Appl. Phys., Acad. of Sci., USSR. (fcs) 85:4988 Katsnel'son, B.G. and L.G. Kulapin, 1984. Average sound-intensity decay law in an irregular underwater acoustic waveguide. Soy. Phys. Acoust. (a translation of Akust. Zh.), 30(5):379-382.
85:4985 Bunchuk, A.V., Yu.Yu. Zhitkovskii and Yu.P. Lysanov, 1984. Distinctive features of the backscattering of sound by a seamount in the open ocean. Soy. Phys. Acoust. (a translation of Akust. Zh.), 30(5):354-357.
Range variations of the average sound intensity are investigated for an 'irregular underwater sound channel' with absorbing surfaces which cause multiple reflections of rays. Cases studied are a shallow sea of variable depth and an irregular near-bottom sound channel. Lenin Komsomol State Univ., Voronezh, USSR. (mjj)
The acoustic backscattering coefficient of a seamount summit followed Lambert's law rather than the LOmmel-Seeliger law that describes shelf-water data, demonstrating that the structure of bottom sediments decisively influences the backscattering of sound. N.N. Andreev Acoust. Inst., Acad. of Sci., USSR. (mwf)
85:4989 Kirlin, R.L. and E.S. Gale, 1985. Analysis of [acoustic signall delay estimation improvement factors due to multiple measurements and a priori information. IEEE Trans. Acoust. Speech Signal Process., ASSP-33(1):46-49.
85:4986 Bunkin, F.V. et al., 1984. Preliminary results of a study of the space--time variability of a shallow sea along a stationary acoustic test range. Sov. Phys. Acoust. (a translation of Akust. Zh.), 30(5):351-353. Preliminary results of low-frequency acoustic probing along a stationary range having a length of several tens of kilometers show that the broadening of the signal spectrum from a low-frequency tone source does not exceed 1.0 × 10-3 Hz. Variations of the phase front of the sound wave in the horizontal plane are observed, attaining 0.5 ° . The spectrum of the signal envelope contains components with periods of 24, 12, 8, and 6 h, along with a broad set of spectral components with periods ranging from several minutes to hours. Inst. of Gen. Phys., Acad. of Sci., USSR. 85:4987 Ivanova, G.K., 1984. Interference strueUn~ of the sound field of a wideband source in a model layered waveguide. Sov. Phys. Acoust. (a translation of Akust. Zh.), 30(5):369-371. The oceanic sound field is investigated as a function of distance and radiation frequency. Calculated parameters including spatial frequencies of interference, mode number and transit times, and their
Signals from distant sources produce intersensor delays in towed arrays, Factors which can improve measurement variances are defined and plotted versus signal-to-noise ratio and number of sensors in the arrays. Clustered versus equally spaced sensors are also investigated. Analytical results are obtained for three sensors. Dept. of Elect. Engrg., Univ. of Wyoming, Laramie, WY 82071, USA. 85:4990 Kobelev, Yu.A. and L.A. Ostrovskii, 1984. Acoustic-electrostatic analogy and the Interaction of gas bubbles in a liquid, Soy. Phys. Acoust. (a translation of Akust. Zh.), 30(5):427-428. Inst. of Appl. Phys., Acad. of Sci., USSR. 85:4991 Zabolotskaya, E.A., 1984. Interaction of gas bubbles in a sound field. Soy. Phys. Acoust. (a translation of Akust. Zh.), 30(5):365-368. A system of nonlinear dynamical equations describing the pulsations of two gas bubbles exerting a mutual influence on one another is derived using the Lagrangian formalism. The normal modes of the system are investigated. The Bjerknes force is determined; its dependence on the distance between the bubbles is analyzed. P.N. Lebedev Phys. Inst., Acad. of Sci., USSR.
A. PhysicalOceanography
A260. Acoustics 85:4984 Ageeva, N.S. and V.D. Krupin, 1984. Behavior of the mode frequency responses in shallow water with variation of the longitudinal wave velocity in the bottom sediment layer and the sound-velocity profile in the water layer. Soy. Phys. Acoust. (a translation of Akust. Zh.), 30(5):341-345. N.N. Andreev Acoustics Inst., Acad. of Sci., USSR.
733
dependence on frequency and distance, are cornpc.red with a theoretical model to describe the spatial-frequency distribution in an acoustic waveguide. Inst. of Appl. Phys., Acad. of Sci., USSR. (fcs) 85:4988 Katsnel'son, B.G. and L.G. Kulapin, 1984. Average sound-intensity decay law in an irregular underwater acoustic waveguide. Soy. Phys. Acoust. (a translation of Akust. Zh.), 30(5):379-382.
85:4985 Bunchuk, A.V., Yu.Yu. Zhitkovskii and Yu.P. Lysanov, 1984. Distinctive features of the backscattering of sound by a seamount in the open ocean. Soy. Phys. Acoust. (a translation of Akust. Zh.), 30(5):354-357.
Range variations of the average sound intensity are investigated for an 'irregular underwater sound channel' with absorbing surfaces which cause multiple reflections of rays. Cases studied are a shallow sea of variable depth and an irregular near-bottom sound channel. Lenin Komsomol State Univ., Voronezh, USSR. (mjj)
The acoustic backscattering coefficient of a seamount summit followed Lambert's law rather than the LOmmel-Seeliger law that describes shelf-water data, demonstrating that the structure of bottom sediments decisively influences the backscattering of sound. N.N. Andreev Acoust. Inst., Acad. of Sci., USSR. (mwf)
85:4989 Kirlin, R.L. and E.S. Gale, 1985. Analysis of [acoustic signall delay estimation improvement factors due to multiple measurements and a priori information. IEEE Trans. Acoust. Speech Signal Process., ASSP-33(1):46-49.
85:4986 Bunkin, F.V. et al., 1984. Preliminary results of a study of the space--time variability of a shallow sea along a stationary acoustic test range. Sov. Phys. Acoust. (a translation of Akust. Zh.), 30(5):351-353. Preliminary results of low-frequency acoustic probing along a stationary range having a length of several tens of kilometers show that the broadening of the signal spectrum from a low-frequency tone source does not exceed 1.0 × 10-3 Hz. Variations of the phase front of the sound wave in the horizontal plane are observed, attaining 0.5 ° . The spectrum of the signal envelope contains components with periods of 24, 12, 8, and 6 h, along with a broad set of spectral components with periods ranging from several minutes to hours. Inst. of Gen. Phys., Acad. of Sci., USSR. 85:4987 Ivanova, G.K., 1984. Interference strueUn~ of the sound field of a wideband source in a model layered waveguide. Sov. Phys. Acoust. (a translation of Akust. Zh.), 30(5):369-371. The oceanic sound field is investigated as a function of distance and radiation frequency. Calculated parameters including spatial frequencies of interference, mode number and transit times, and their
Signals from distant sources produce intersensor delays in towed arrays, Factors which can improve measurement variances are defined and plotted versus signal-to-noise ratio and number of sensors in the arrays. Clustered versus equally spaced sensors are also investigated. Analytical results are obtained for three sensors. Dept. of Elect. Engrg., Univ. of Wyoming, Laramie, WY 82071, USA. 85:4990 Kobelev, Yu.A. and L.A. Ostrovskii, 1984. Acoustic-electrostatic analogy and the Interaction of gas bubbles in a liquid, Soy. Phys. Acoust. (a translation of Akust. Zh.), 30(5):427-428. Inst. of Appl. Phys., Acad. of Sci., USSR. 85:4991 Zabolotskaya, E.A., 1984. Interaction of gas bubbles in a sound field. Soy. Phys. Acoust. (a translation of Akust. Zh.), 30(5):365-368. A system of nonlinear dynamical equations describing the pulsations of two gas bubbles exerting a mutual influence on one another is derived using the Lagrangian formalism. The normal modes of the system are investigated. The Bjerknes force is determined; its dependence on the distance between the bubbles is analyzed. P.N. Lebedev Phys. Inst., Acad. of Sci., USSR.