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Journal Articles Acta Acustica united with Acustica Year : 1996

Inversion of a cylindrical vibrating body in shallow water from aspect-limited data using filtered SVD and the L-curve

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Abstract

The distribution of the normal velocity of a cylindrical vibrating body in a shallow water waveguide is retrieved from nearfield pressures sampled by a vertical array of hydrophones placed on one side of the body only and which partially covers the water column between the bottom (fluid penetrable) and the air surface (pressure-release). A contour integral formulation of the wavefield whose Nyström method yields the discrete counterpart is used, the Green's function of the layered environment being calculated by fast Fourier transforms for nonequispaced data. The ill-posed linear inversion is performed by filtered Singular Value Decomposition, an optimum Tikhonov's regularization parameter being determined by the L-curve. Circular and elliptic contours and several types of vibration are simulated at a low and a high frequency. Regularization is needed for small sampling steps or large data errors. The inversion method appears robust against measurement noise and uncertainty on each hydrophone location, with a generally good though often underestimated regularization parameter. In addition, strong transmission in the bottom and a short receiver array (down to one-fifth of the water column) are factors which do not degrade the results significantly with respect to those obtained with a hard bottom and an array spanning half or more of the column.
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Dates and versions

hal-00641656 , version 1 (16-11-2011)

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  • HAL Id : hal-00641656 , version 1

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Christophe Rozier, Dominique Lesselier. Inversion of a cylindrical vibrating body in shallow water from aspect-limited data using filtered SVD and the L-curve. Acta Acustica united with Acustica, 1996, 82 (5), pp.717-728. ⟨hal-00641656⟩
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