Resonance identifications of a solid axisymmetric finite length target

Acoustic resonance scattering from a water‐immersed, solid tungsten carbide target in the form of a finite‐length circular cylinder terminated by two hemispherical endcaps has been studied experimentally, and analyzed theoretically. The resonance frequencies have been determined from the condition of phase matching of the generated surface waves encircling the object; for the surface waves propagating over its cylindrical portion in the axial direction, the dispersion has been properly taken into account, as well as that of surface waves on the spherical surfaces. Surface displacements corresponding to the standing waves at each resonance were determined, and were used to calculate the angular patterns of the scattered acoustic field, in excellent agreement with the observed angular distributions. The pattern of lobes is found to provide information on the mode N of the standing surface waves, although in a less straightforward fashion than this had been the case in previous studies for the simple example...