Termination impedance of open-ended cylindrical tubes at high sound pressure level

The study deals with nonlinear acoustical effects localised at the open-end of a cylindrical tube. The termination impedance is measured using a two microphone method. Due to the separation of the acoustic flow at the pipe end, the real part of the termination impedance depends on the volume velocity at the open end. It is shown that the radius of curvature of the edges of the open end of the tube has a crucial influence on the amplitude of the nonlinear losses. Several regimes are shown for the low radii of curvature.