Accession Number : ADA310720

Title :   Geometrical Aspects of Scattering and Physical Effects of Sound.

Descriptive Note : Summary rept. 1 Jun 95-31 May 96,

Corporate Author : WASHINGTON STATE UNIV PULLMAN DEPT OF PHYSICS

Personal Author(s) : Marston, Philip L.

PDF Url : ADA310720

Report Date : 15 JUN 1996

Pagination or Media Count : 16

Abstract : Research is reported in the following areas: 1 Transient and high-frequency enhancements of the scattering of sound by elastic objects in water are measured and analyzed. (The impulse response of a thick cylindrical shell in water was measured as a function of aspect angle. The measurements show the frequency locus of a backscattering enhancement extending to near end-on incidence in agreement with predictions for an antisymmetric leaky Lamb wave. Other enhancements and supporting theoretical developments are noted.) 2 New measurements and theoretical work on the interaction of sound with sound mediated by an aqueous suspension display coherent scattering effects for a range of conditions. 3 The coupling of an oscillating magnetic field to the quadrupole quasi-flexural mode of a shell in air is investigated. (An acoustic signature produced by shell vibrations in response to an oscillating Maxwell stress is easily detected even without the static bias magnetic field normally used in an EMAT.) 4 An oscillating electric field is used to excite the monopole mode of bubbles in an insulating liquid. (As with item (3), the method may be useful for measuring mode frequency and damping where exact solutions are not known.)

Descriptors :   *ACOUSTIC SIGNATURES, *ACOUSTIC SCATTERING, *RAYLEIGH WAVES, ELECTROMAGNETIC FIELDS, MAGNETIC FIELDS, VIBRATION, OPTIMIZATION, ACOUSTIC WAVES, ELASTIC PROPERTIES, ELECTRIC FIELDS, QUADRUPOLE MOMENT, BACKSCATTERING, SHELLS(STRUCTURAL FORMS), SUSPENDED SEDIMENTS, BUBBLES, ACOUSTIC IMAGES, ACOUSTIC MEASUREMENT, UNDERWATER ACOUSTICS, SOUND PRESSURE, FREQUENCY RESPONSE, ASPECT ANGLE, BRAGG SCATTERING, SOUND RANGING, ACOUSTIC RESONANCE.

Subject Categories : Acoustic Detection and Detectors
      Acoustics

Distribution Statement : APPROVED FOR PUBLIC RELEASE