ASA 125th Meeting Ottawa 1993 May

5aSA11. Influence of endcaps on mid-frequency scattering from finite cylindrical shells at axial incidence.

Matthew Conti

Y. P. Guo

Ira Dyer

Dept. of Ocean Eng., MIT, Cambridge, MA 02139

Experimental studies of mid-frequency scattering from cylindrical shell models at axial incidence have demonstrated the excitation of axisymmetric compressional and flexural waves within the endcap. The endcap discussed here consists of spherical and conical sections connected to the cylindrical portion of the shell model via slope discontinuities. Phase-matched coupling to compressional waves occurs on the spherical portion of the endcap. Scattering to both wave types occurs at the slope discontinuities. Conical shell dispersion equations developed by Guo are shown to match experimental observations. The Wigner transform is used to demonstrate these phenomena. Amplitude and group delay effects are discussed. The bistatic measurements were conducted over a frequency range of 2.5