Peter Risby Andersen (DTU/ CAMM) presents: A newly developed acoustic tangential hyper singular boundary element formulation including viscous losses.
Numerical modeling of thermoviscous losses has become gradually more important with the trend of reducing the size of acoustic devices. Both finite and boundary element formulations exist that includes thermoviscous losses. Especially, boundary element is an attractive method, since it avoids an expensive meshing of boundary layers. But one of the potential short comings of the boundary element implementations is the use of simple first and second order tangential finite difference pressure derivatives to couple the fundamental equations. In this presentation a new direction for the thermoviscous boundary element formulation is presented utilizing a tangential derivative hypersingular boundary element formulation, avoiding the need for the finite difference coupling and evaluation of second order tangential derivatives. But unfortunately the hypersingular boundary element formulation adds new difficulties, hypersingular integration kernels can be difficult to evaluate and C1 continuity becomes a must. The presentation will discuss the new approach with simple simulation examples and present ideas on how to overcome its difficulties.