Application of the modified infinite element method to two-dimensional transient acoustic radiation

Methods in Solving the Wave Equations for A Loudspeaker

“…Astley et al [14], [15] and Li [16] used infinite wave envelope elements combined with conventional finite elements to model the transient wave equation in unbounded regions. The method was based on a Fourier transform of the wave envelope approach applied to steady wave problems and was valid over a full range of excitation frequencies.…”

Diffraction of sound by a poroelastic cylindrical absorber near an impedance plane

“…Moreover, the field scattered by the poroelastic cylinder, in presence of the image cylinder, is conveniently expressed in the form where A n (o) are unknown scattering coefficients and H n (x) ¼ J n (x)+iY n (x) is the cylindrical Hankel function of order n [39], whose asymptotic form for large values of the argument [39], lim x!1 H n ðxÞ ¼ ffiffiffiffiffiffiffiffiffiffi ffi 2=px p exp½ix À iðp=4Þ ð2n þ 1Þ, clearly indicates that the scattered field satisfies Sommerfeld radiation condition at infinity. This condition, which manifests the characteristic of the wave problem (the decay of waves) in far field, is commonly imposed to ensure the uniqueness of the solution in exterior acoustic scattering problems [40,41]. The reflection of this scattered wave by the flat surface (i.e., the field scattered by the image cylinder) may be written as [35,42] …”