Absorption Properties of Helmholtz Resonator at High Amplitude Incident Sound

The sound attenuation in a Helmholtz resonator subjected to a plane incident wave is examined. The resonator closing a tube is considered. The average acoustic power absorbed by vortical field has been calculated in the low frequency range with the aid of the appropriate conservation equations. Considering this power loss and losses due to viscous damping inside the resonator orifice, the change of absorption properties of the resonator is analyzed. Results of this study indicate that the peak of the absorption coefficient occurs when the loss resistance is equal to the radiation resistance. Plots of the theoretically predicted absorption coefficient and normalized loss resistance as a function of incident pressure amplitude are in good agreement with experimental data obtained for different orifice diameters.