A combined LDA and flow-visualization study on flue organ pipes

Temporally resolved schlieren flow visualization and Laser-Doppler Anemometry (LDA) measurements have been performed on real flue organ pipes during the stationary state as well as during the attack transient. The techniques prove highly efficient in providing information on the details of the flow. The measurements reveal several details of the flow and demonstrate its importance in the sound formation. The spatial development of harmonics as well as the influence of nicks is also studied. It turns out that the jet instability wave behaves differently when the jet moves inward and outward of the pipe.