Acoustic scattering by axisymmetric finite-length bodies with application to fish : measurement and modeling
Reeder, D. Benjamin
MetadataShow full item record
This thesis investigates the complexities of acoustic scattering by finite bodies in general and by fish in particular through the development of an advanced acoustic scattering model and detailed laboratory acoustic measurements. A general acoustic scattering model is developed that is accurate and numerically effcient for a wide range of frequencies, angles of orientation, irregular axisymmetric shapes and boundary conditions. The model presented is an extension of a two-dimensional conformal mapping approach to scattering by irregular, finite-length bodies of revolution. An extensive series of broadband acoustic backscattering measurements has been conducted involving alewife fish (Alosa pseudoharengus), which are morphologically similar to the Atlantic herring (Clupea harengus). A greater-than-octave bandwidth (40-95 kHz), shaped, linearly swept, frequency modulated signal was used to insonify live, adult alewife that were tethered while being rotated in 1-degree increments over all angles of orientation in two planes of rotation (lateral and dorsal/ventral). Spectral analysis correlates frequency dependencies to morphology and orientation. Pulse compression processing temporally resolves multiple returns from each individual which show good correlation with size and orientation, and demonstrate that there exists more than one significant scattering feature in the animaL. Imaging technologies used to exactly measure the morphology of the scattering features of fish include very highresolution Phase Contrast X-rays (PCX) and Computerized Tomography (CT) scans, which are used for morphological evaluation and incorporation into the scattering modeL. Studies such as this one, which combine scattering models with high-resolution morphological information and high-quality laboratory data, are crucial to the quantitative use of acoustics in the ocean.
Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution June 2002
Showing items related by title, author, creator and subject.
Mikhalevsky, Peter N.; Sagen, Hanne; Worcester, Peter F.; Baggeroer, Arthur B.; Orcutt, John A.; Moore, Sue E.; Lee, Craig M.; Vigness-Raposa, Kathleen J.; Freitag, Lee E.; Arrott, Matthew; Atakan, Kuvvet; Beszczynska-Moller, Agnieszka; Duda, Timothy F.; Dushaw, Brian D.; Gascard, Jean-Claude; Gavrilov, Alexander N.; Keers, Henk; Morozov, Andrey K.; Munk, Walter H.; Rixen, Michel; Sandven, Stein; Skarsoulis, Emmanuel; Stafford, Kathleen M.; Vernon, Frank L.; Yuen, Mo Yan (Arctic Institute of North America, 2015)The dramatic reduction of sea ice in the Arctic Ocean will increase human activities in the coming years. This activity will be driven by increased demand for energy and the marine resources of an Arctic Ocean accessible ...
Slavinsky, Mark; Bogolubov, Boris; Alelekov, Igor; Pigalov, Konstantin; Spiesberger, John L.; Boutin, Paul (Woods Hole Oceanographic Institution, 1993-02)A compact electromagnetic monopole source, requiring pressure equalization, was evaluated at the Naval Underwater Systems Center at Lake Seneca during July 1992 by scientists from the Institute of Applied Physics of the ...
Quantification of the spatial and temporal evolution of stratified shear instabilities at high Reynolds number using quantitative acoustic scattering techniques Fincke, Jonathan R. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2015-02)The spatial and temporal evolution of stratified shear instabilities is quantified in a highly stratified and energetic estuary. The measurements are made using high-resolution acoustic backscatter from an array composed ...