Experimental Demonstration of Generation and Propagation of Acoustic Solitary Waves in an Air-Filled Tube

Experiments are performed to demonstrate the generation and propagation of acoustic solitary waves in an air-filled tube with a periodic array of Helmholtz resonators connected axially. The purpose is to verify the theoretical findings made so far that nonlinear acoustic waves do not evolve into a shock but into a solitary wave propagating steadily without any change of its smooth profile. To identify the solitary wave, the temporal pressure profile is compared directly with the theoretical profile of the solitary wave. Also checked are the relation between the peak sound pressure of the solitary wave and its half-value width in time, and the relation between the peak sound pressure and the deviation of propagation speed from sound speed. The experimental results show good quantitative agreement with the theory.