Numerical comparison of acoustic infinite elements

Numerical studies of various infinite element formulations are conducted: conjugated types, unconjugated, decay (unconjugated), and DAA1 elements of the Olsen/Bathe type. In addition, an ‘‘element’’ implementing the Bayliss et al. first‐order condition is studied. All elements except the decay are implemented in separable coordinates. The element formulations are studied analytically, using axisymmetric modal impedances of a sphere. These studies reveal limitations, advantages, and appropriate methods of usage for the various formulations. Subsequently, the various elements are implemented in production‐type software, and numerical comparisons are conducted. These studies reveal the relative accuracy of the formulations as well, but also permit discussion of numerical performance. Fully coupled, three‐dimensional structural acoustic meshes are studied. Comparisons are made against a BEM method, and analytic solutions where appropriate. When used properly, infinite element methods can deliver accuracy comp...