Park K., Lee M., Park Y.

A second-order coupled acoustic pressure model interacting with flexible structures derived in the companion paper, Part I, is evaluated for its fidelity. For evaluation purposes, an isotropic elastic spherical shell that is subject to a doublet source acting on the shell surface is employed as this problem has its exact mode-by-mode solutions in terms of Legendre functions. When the present model is specialized to a first-order pressure equation, the resulting present model exhibits significantly improved radiation damping compared with the so-called first-order Doubly Asymptotic Approximation (DAA1) model. For the assessment of the model fidelity, mode-by-mode characteristic roots of the coupled systems are computed for the exact solutions, the DAA2 and the present second-order model. The evaluation results show that: (1) the present second-order model capture the dominant acoustic scattering pressure modes; (2) the second-order Doubly Asymptotic Approximation (DAA2) model fails to capture the important oscillating pressure higher modes; (3) the two model parameters can be adjusted to capture certain desirable pressure modes more accurately depending on the problem at hand; (4) hence, the present second-order model is recommended for use in inverse problems for identifying the sound sources, in addition to the computations of the structural responses subject to external acoustic shocks and explosions.