The Journal of the Acoustical Society of Korea

The Acoustical Society of Korea (한국음향학회)
권호 표지

Wave Reflection from Porous Ocean Sediment With Depth Dependent Properties

깊이 방향의 변화가 있는 해저 퇴적물에서 반사 특성

  • Lee, Keun-Hwa (Dept. of Naval Architecture and Ocean Engineering, Seoul National University) ;
  • Seong, Woo-Jae (Dept. of Naval Architecture and Ocean Engineering, Seoul National University)
  • Published : 2006.03.31
Download PDF
⟨ Previous Next ⟩

Abstract

This study examines the reflection characteristic of a thin transition layer of the ocean bottom showing variability with respect to depth. In order to model the surficial sediment simply, we reduce the Biot model to the depth dependent wave equation for the pseudo fluid using the fluid approximation (weak frame approximation). From the reduced equation, the difference between the inherent frequency dependency of the reflection and the frequency dependency resulting from a thin transition layer is investigated. Using Tang's depth porosity profile model of the surficial sediment [D. Tang et al., IEEE J. Oceanic Eng., vol.27(3), 546-560(2002)], we numerically simulated the reflection loss and investigated the contribution from both frequency dependencies. In addition, the effects of different sediment type and varying depth structure of the sediment are discussed.

Keywords

References

  1. R. D. Stoll, Sediment acoustics, Springer- Verlag, (NY, 1989)
  2. L. M. Brekhovskikh, Waves in layered media, Academic, (NY, 1980)
  3. A. p. Lyons and T. H. Orsi, 'The effect of a layer of varying density on high-frequency reflection, forward loss, and backscatter,' IEEE J. Oceanic Eng., 23 (4), 411-422, 1998 https://doi.org/10.1109/48.725235
  4. D. Tang, K. B. Briggs, K. L. Williams, D. R. Jackson, E. I. Thorsos, and D. B. Percival, 'fine-scale volume heterogeneity measurements in sand,' IEEE J. Oceanic Eng., 27 (3), 546-560, 2002 https://doi.org/10.1109/JOE.2002.1040937
  5. N. P. Chotiras, 'Inversion and sandy ocean sediment,' in Full Field Inversion Methods in Ocean and Seismo Acoustics, edited by O.Diachok, A. Caiti, P, Gerstoft, and H. Schmidt (Kluwer, Dordrecht, 1995), 353-358
  6. R. Carbo, 'Wave reflection from a transitional layer between the seawater and the bottom,' J. Acoust, Soc. Am., 101 (1), 227 https://doi.org/10.1121/1.418005
  7. Masao Kimura and Takuya Tsurumi, 'Characteristics of acoustic wave reflection from the transition layer of surficial marine sediment,' in Proc. Underwater Technology 2002, 225-230
  8. F. B. Jensen, W. A. Kuperman, M. B. Porter, and H. Schmidt, Computational ocean acoustics, (AlP, NY, 1993)
  9. M. Stern, A. Bedford, and H. B. Millwater, 'Wave reflection from a sediment layer with depth-dependent properties,' J. Acoust. Soc. Am., 77 (5), 1781-1788, 1985 https://doi.org/10.1121/1.391927
  10. J. M. Hovem and G. D. Ingram, 'Viscous attenuation of sound in saturated sand,' J. Acoust, Soc. Am., 66 (6), 1807-1812, 1979 https://doi.org/10.1121/1.383653
  11. K. L. Williams, 'An effective density fluid model for acoustic propagation in sediments derived from Biot theory,' J. Acoust. Soc. Am., 110 (5), pt1, 2276-2281, 2001 https://doi.org/10.1121/1.1412449
  12. S. R. Rutherford and K. E. Hawker, 'Effects of density gradients on bottom reflection loss for a class of marine sediments,' J. Acoust. Soc. Arn., 63 (3), 750-757, 1978 https://doi.org/10.1121/1.381783
  13. M. D. Richardson, D. K. Young, and K. B. Briggs, 'Effects of hydrodynamic and biological processes on sediment geoacoustic properties in long island sound, U.S.A.,' Marine Geology, 52, 201-226, 1983 https://doi.org/10.1016/0025-3227(83)90056-7