Analysis of convergence and accuracy of the DRBEM for axisymmetric Helmholtz–type equation. Engineering analysis with boundary element methods

This paper presents a study of the convergence properties of a new axisymmetric approximating function. This function, associated with a dual reciprocity boundary element model for axisymmetric Helmholtz-type equation, is independent of the wave number in order to avoid occasional singular matrix due to some particular wave numbers. Interpolation functions are derived from the approximating functions. Their properties are studied numerically and their local behaviour is illustrated. Numerical tests, carried out in the last section, show a reasonably good agreement with analytical solutions of two simple aeroacoustic problems. Some criteria concerning the number of nodes per wave