Numerical simulation of nonlinear acoustic attenuation of multi-component gas mixture

The direct simulation Monte Carlo(DSMC) method was introduced to model the acoustic propagation in multi-component gas mixture.And a theoretical predictive model of acoustic attenuation was developed,which is independent of experiential parameters.The acoustic attenuation spectra of various multi-component gas mixtures, consisting of nitrogen,oxygen,carbon dioxide,methane and water,were estimated by the DSMC method.The sound frequency range of interest is from 8 MHz to 232 MHz.Compared with the result of the relaxation attenuation based on the DL model plus that of the classical attenuation calculated by the Stokes-Kirchhoff formula,the estimations of acoustic attenuation of our model agreed with them.The precision of the model depends upon the knowledge of the physical mechanism of molecule collision from which the attenuation arises.In addition,the result of our model shows that the characters of the frequency-dependent acoustic attenuation rely on the composition of the gas mixtures.And this could lead to the development of smart acoustic gas sensors capable of quantitatively determining gas composition in various environments and processes.