Figure 3
Transverse distributions: (a) Measured radial distributions of the sound pressure (circles) and their best-fit curves (solid lines) for 6295 Hz and 7320 Hz. Each measured data series is normalised to its own maximum value. (b) Sound pressure along the diameter in the corrugated waveguide (top) and in the straight duct (bottom) for 6910 Hz. The circles represent the measured pressures normalised to the maximum values of their corresponding data series and the solid lines represent the theoretical distributions of the second and first modes in the top and bottom portions, respectively.
