Accession Number : AD1049148


Title :   Acoustic Wave Dispersion and Scattering in Complex Marine Sediment Structures


Descriptive Note : Technical Report,15 Mar 2014,31 Dec 2017


Corporate Author : Pennsylvania State University Applied Research Laboratory University Park


Personal Author(s) : Holland ,Charles W


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/1049148.pdf


Report Date : 21 Mar 2018


Pagination or Media Count : 4


Abstract : Major challenges in testing dispersion theories against measured data include separating the competing effects of structures that occur in virtually all natural marine sediments including discrete layering, gradients (sound speed, attenuation and density), shear waves, interface roughness, sediment volume heterogeneities (sub-wavelength scale), lateral variability (many wavelength scale) and anisotropy. All of these effects exhibit their own frequency dependence and if ignored, can badly bias dispersion estimates. One of the competing effects, sediment volume scattering, is important not only for establishing the correct frequency dependence of the attenuation, but also crucial for understanding long-range reverberation prediction. Recent evidence has suggested that sediment volume scattering is a dominant mechanism for controlling the frequency dependence of reverberation. The long-term goal of the research is to substantively improve understanding of the physical mechanisms that control propagation and scattering in the seabed.


Descriptors :   Acoustic Waves , acoustic scattering , sediments , geoacoustics , heterogeneity , acoustic propagation , reverberation , seabed , roughness


Subject Categories : Physical and Dynamic Oceanography
      Acoustics


Distribution Statement : APPROVED FOR PUBLIC RELEASE