Application of Wave Based Technique for a cavity considering forced excitation at boundaries and effects of absorption materials

The Wave Based Technique (WBT) is a novel prediction technique for steady-state acoustic analysis, which is based on the indirect Trefftz approach. Recently, a methodology has been developed, which allows to consider a 3-dimensional fluid domain with prescribed normal velocity and prescribed normal impedance boundary conditions. For this methodology, it is necessary that the acoustic problem domain is convex. To extend the application field of the WBT methodology a new prescribed velocity boundary condition is introduced in order to consider the structural local distribution of vibration velocities at the boundaries. The velocity distributions can be derived from either measurement data or from results of structural FEM analyses. By using this new boundary condition the excitation of the fluid due to structural vibrations can be considered. For validation purposes, a car-like cavity (Sound Brick) was designed. Results of FEM calculations and measurements were compared to those of the WBT.