A wave-based analysis for acoustic transmission for fluid-filled elastic waveguides

This paper describes an original numerical prediction technique developed for the analysis of coupled vibro-acoustic problems in fluid waveguides. Specifically it is is a wave-based method. Unlike the conventional element-based methods, this technique uses wave functions that satisfy the governing equations to describe the dynamic variables exactly. One advantage is that fine domain discretizations, used by element based methods near the fluid-structure interface typically, are no longer required. Hence the resulting model sizes are much smaller than element based methods yielding a more time-efficient prediction technique that may allow handling of mid-frequency applications. Another advantage is that dispersion relations between propagating wavenumbers and excitation wavenumbers are easily obtained and an example to show this is presented. Also a discussion on how the wave-based prediction technique can be used for coupled vibro-acoustic problems a cavity with a non-reflecting boundary and a complex silencer duct problem. Its beneficial characteristics compared to element-based methods are demonstrated through the validation study and transmission loss examples.