Examination of organ flue pipe resonator eigenfrequencies by means of the boundary element method

The aim of the investigations is the application of numerical methods for organ flue pipe research. The radiated sound of a flue pipe is very complex, affected by not only acoustical but also flow parameters. In order to reduce the problem comlplexity, a representative detail of the entire sound generating mechanism was selected, which can be numerically modelled. The eigenfrequency structure of a flue pipe resonator is a predominant component of the radiated sound spectrum and especially convenient for numerical simulations. The measurement procedure of the resonator frequency response (external acoustic excitation) was modelled by means of the Boundary Element Method and the obtained eigenfrequencies were verified by real measurement data. The effects of different tuning devices were examined by means of the mentioned method.