Time‐domain scattering from tungsten‐carbide targets

Scattering calculations are almost exclusively performed in the frequency domain. Although form functions are computed regularly, they are rarely utilized to obtain time‐domain results. This is surprising because the payoff for the small amount of extra effort required for Fourier synthesis includes results that are easy to interpret in terms of causality. This approach will be used to study resonances of tungsten‐carbide spheroids for aspect ratios ranging from 1–6 and for kL/2 up to 26. Tone bursts, cw pings, and Gaussian sources will be utilized to isolate resonances and to determine their nature. An analysis of arrival time as a function of aspect ratio gives credibility to the interpretation that resonances induced along the axis of symmetry are due to Rayleigh waves as first proposed by Flax et al. [J. Acoust. Soc. Am. 71, 1077–1082 (1982)]. [Work supported by the Naval Ocean Research and Development Activity.]