Direct hybrid coupled finite element - wave based technique for 3D steady-state acoustic analysis

As alternative to the well known finite element method (FEM) the recently developed wave based technique (WBT) has proven to be a computationally efficient tool for steady-state acoustic analysis. To overcome the moderate geometrical complexity restriction of WBT a hybrid coupling method between FEM and WBT has been developed. This coupling approach benefits from the advantages of both methods combining the flexibility of FEM for complex geometries and of the computational efficiency of WBT. This paper describes the extensions necessary for the 3D hybrid coupling method originally developed for 2D problems. Specifically, the characteristic of the coupling matrices for the direct coupling method of FEM and WBT is described. First results of application examples considering different boundary conditions are discussed. The results of the hybrid coupled method are validated by results of pure WBT simulation and by measurements.