Theoretical and experimental studies of surface waves on solid-fluid interfaces when the value of the fluid sound velocity is located between the shear and the longitudinal ones in the solid

The existence of two surface waves propagating on a plane solid-fluid inter face is demonstrated when the value of the fluid sound velocity is located between the shear and the longitudinal ones in the solid. First, the Scholt e-Stoneley dispersion equation is studied analytically and numerically to f ind the roots corresponding to the Stoneley and the Rayleigh waves. The ana tomy of each one is then described with the formalism of the evanescent pla ne waves: both waves are unleaky. Finally, the results are confirmed experi mentally by measuring the times of flight on a Plexiglas-water interface an d on a PVC-water interface. (C) 1999 Acoustical Society, of America. [S0001 -4966(99)02607-7].