Accession Number : ADA257928


Title :   Radiation and Scattering at Oblique Incidence from Submerged Oblong Elastic Bodies


Descriptive Note : Final rept.


Corporate Author : NAVAL OCEANOGRAPHIC AND ATMOSPHERIC RESEARCH LAB STENNIS SPACE CENTER MS


Personal Author(s) : Uberall, Herbert ; Bao, X L ; Miller, Russel D ; Werby, Michael F


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a257928.pdf


Report Date : Mar 1992


Pagination or Media Count : 10


Abstract : The resonant behavior of solid or hollow oblong submersed elastic objects is studied both theoretically and experimentally. The resonances have been studied directly, by a calculation of surface wave displacements, or inferentially, by calculations or observations of echoes from plane incident acoustic waves with axial, broadside, or general oblique incidence onto the submersed objects. For the latter, we considered solid or hollow spheroids, or cylinders with flat or with hemispherical ends. Resonances are obtained theoretically from the phase matching of surface waves, which physically form standing waves in this case. A bar wave picture of resonant vibration has also been considered; it is shown to apply in the low-ka region while surface wave pictures apply in the high-ka region while surface wave pictures apply in the high-ka region, and the two pictures merge in the intermediate region. The dispersion of surface waves along the object for axial incidence is treated exactly. For broadside incidence, simultaneous excitation of meridional and circumferential surface wave is noted. The same surface wave picture applies for sound radiation from these objects following point excitation. Acoustic scattering, shallow water, waveguide propagation.


Descriptors :   *RESONANCE SCATTERING , *UNDERWATER ACOUSTICS , PROPAGATION , RADIATION , SCATTERING , VIBRATION , SURFACE WAVES , MODULUS OF ELASTICITY , SHELLS(STRUCTURAL FORMS) , SOLIDS , RODS , BEHAVIOR , ACOUSTICS , SOUND , CYLINDRICAL BODIES , ECHOES , SHALLOW WATER , SURFACES , PHASE , STANDING WAVES , DISPERSIONS , UNDERWATER STRUCTURES , MATCHING , ACOUSTIC SCATTERING , SPHERES , WAVEGUIDES , WATER , EXCITATION , ACOUSTIC WAVES , DISPLACEMENT , OBSERVATION


Subject Categories : Acoustics


Distribution Statement : APPROVED FOR PUBLIC RELEASE