Theoretical study of the Stoneley-Scholte wave at the interface between an ideal fluid and a viscoelastic solid

International audienceThe propagation of the Stoneley-Scholte wave is analysed at the boundary between an ideal fluid and a viscoelastic solid. The theoretical study is developed using the approach of the inhomogeneous plane waves: the interface wave is thus regarded as a linear combination of one evanescent wave in the fluid and two heterogeneous waves in the solid. The main interest of the paper is the introduction of the viscoelastic solid, which is a medium characterized by physical attenuation, in the study of the propagation of the interface wave. Its mechanical viscosities are expressed in terms of acoustical attenuations, more easily determined by means of acoustical measurements. Existing mathematical tools are then used for solving the dispersion equation determined in this case. The study presented in the paper deals only with some aspects of the direct problem, that is the determination of the propagation properties of the Stoneley-Scholte wave, established for two different interfaces. A comparison of these characteristics in the presence and in the absence of attenuation, and a parametric study of the effect of attenuation, are included. The validity of the theoretical results are finally well demonstrated with some experimental ones, obtained with synthetic resins modelling viscoelastic solids