Proceedings of Meetings on Acoustics

Measurements of the back scattering by bluntly-truncated tilted cylindrical shells in water reveal a dependence on the aspect angle which can be interpreted using geometrically described coupling mechanisms [S.F. Morse, P.L. Marston, and G. Kaduchak, J. Acoust. Soc. Am. 103, 785-794 (1998)]. By exciting a shell with a suitable acoustic pulse localized in time, the recorded backscattering response reveals a significant evolution of the spectrum as a function of time and tilt angle. This evolution was interpreted using the dispersion relations of the relevant highfrequency shell guided waves [S.F. Morse and P.L. Marston, J. Acoust. Soc. Am. 111, 1289-1294 (2002)]. The coupling conditions are affected by the mode properties. This interpretation was facilitated by also computing the scattering properties of an infinitely long titled shell [S.F. Morse and P.L. Marston, J. Acoust. Soc. Am. 106, 2597-2600 (1999)] and by measuring and modeling the contributions of helical and meridional rays [S.F. Morse and P.L. Marston 112, 1318-1326 (2002); F. J. Blonigon, P.L Marston, 112, 528-536 (2002)]. One of the shells investigated was also convenient for a quasi-holographic imaging of the bistatic scattering of short pulses [K. Baik, C. Dudley, and P.L. Marston, 130, 3838-3851 (2011)].