Numerical integration methods for the solution of Helmholtz equations with the Wave Based Technique

Regular paper

AVL List GmbH

Monday 1 june, 2015, 15:20 - 15:40

0.7 Lisbon (47)

Abstract:

The Wave Based Technique is a method for airborne noise simulation, which is
aimed for applications in the low- and mid-frequency range. The main focus of
this article is on application to sound radiation of internal combustion
engines.
The discretization of the Helmholtz equation, which is the basis for the Wave
Based Technique, requires the computation of certain surface integrals with high
accuracy using numerical quadrature rules. Structural vibrations of a given
surface (e.g. the surface of an engine block), have to be mapped to the
integration points. With increasing frequency the number of integration points
in these quadratures has to be increased to achieve the desired accuracy. Every
time the integration points are increased the mapping procedure has to be done
anew. To save computational time it is therefore desirable to reuse of the
integration points and the already computed mapping information whenever this is
possible.
This paper demonstrates different strategies to reuse all or a subset of the
integration points in order to increase the performance. The application of
these strategies is benchmarked using a model of an inline 4-cylinder Diesel
engine. An analysis of how the new strategies affect the simulation results is
done and performance is compared to the straightforward approach in which no
reuse of integration points is done.