Fast Multipole Boundary Element Acoustics

Multipole BEM (Boundary Element Method) is a boundary element technique that specifically addresses ultra-large BEM problems. This new technique complements existing BEM techniques: a classical BEM solver can address BEM models up to 20 000 nodes efficiently, where the advanced LMS Virtual.Lab Fast Multipole Boundary Element solver can handle models up to one million nodes and more. In this way, larger problems regarding higher frequencies can be tackled, which makes the BEM method very scalable.

The fast Multipole BEM module implements high-speed iterative techniques to solve the BEM equations, with additional sophisticated algorithms based on multipole expansion and multi-level hierarchical cell substructuring. Instead of solving the model in one go, the module automatically splits up the model in domains, which in turn are

split up again and again. Each small domain is treated as a classical BEM model. A translator operator describes the relation between the domains and the fast iterative algorithm solves the complete model. The total computation time is quasi linear to the number of nodes of the BEM model, which requires less memory. The model is running on Windows PCs, multi-CPU systems and clusters.

With this technique, running models becomes faster and a complete new set of applications can be addressed, such as the study of exterior acoustics of complete vehicles up to several 1000Hz, aircrafts, ships, submarines, large engines including enclosures, turbines and more.