Effects of nonlinear parameter of fluid-solid coupling on acoustic field in porous media (L)

The purpose of this Letter to the Editor is to demonstrate the effects of the nonlinear parameter of fluid-solid coupling on the acoustic field in porous media. The nonlinear acoustic field excited by a one-dimensional finite-amplitude shear wave propagating in the uniform and infinite saturated porous media is studied. Researchers use the complete strain energy formula with third-order terms of strain in saturated porous media. The formula for calculating the fluid-solid coupling nonlinear parameter gamma from the dynamic compatibility condition is given. To illustrate the effect of the fluid-solid coupling nonlinear term on the nonlinear acoustic field excited by the longitudinal and transverse waves, this study compares nonlinear acoustic fields excited by a finite amplitude wave with and without nonlinear parameter gamma. The results show that the nonlinear parameter gamma has an influence on the nonlinear acoustic field excited by the one-dimensional shear wave, but it has no influence on the nonlinear acoustic field excited by the one-dimensional longitudinal wave. (C) 2020 Acoustical Society of America.