4aSA7. High-frequency backscattering by thick finite cylindrical shells in water at oblique incidence: Experiments and calculations.

Session: Thursday Morning, May 16

Time: 9:45

Author: Scot F. Morse
Author: Philip L. Marston
Location: Phys. Dept., Washington State Univ., Pullman, WA 99164-2814
Author: Gregory Kaduchak
Location: Univ. of Texas, P.O. Box 8029, Austin, TX 78713-8029


Various authors have demonstrated the importance of plotting backscattering amplitude as a function of both aspect angle and frequency for thin cylindrical shells in water. Some interesting features of analogous plots for a thick finite cylindrical shell with the frequency range extending above the coincidence region have been investigated. Impulse response measurements taken with an improved PVDF sheet source [Kaduchak et al., J. Acoust. Soc. Am. 97, 2699--2708 (1995)] reveal a backscattering enhancement in the coincidence frequency region for aspect angles in the vicinity of end-on incidence. Though the cylinder was capped, the features of interest appear to be identified with waves on the coupled shell--fluid system. Similar features are present in backscattering computations for a simply supported thick cylindrical shell and they may be useful in high-frequency inverse scattering. [Sponsored in part by the Office of Naval Research and by the UT:ARL Independent Research and Development Program.]

from ASA 131st Meeting, Indianapolis, May 1996