Theoretical and experimental study of ultrasonic surface modes at a solid-fluid periodic interface

The generation of ultrasonic surface waves on a solid-liquid periodic interface is demonstrated. Characterization of leaky Stoneley modes and leaky Rayleigh modes is obtained by looking at the reflected and the transmitted broadband spectra. It is shown both experimentally and theoretically that the frequency and amplitude of such surface resonances are significantly affected, not only by the spatial periodicity of the profile, but also by the peak-to-valley height of the roughness. As a result, the practical problem of measurement of the geometrical parameters of the periodic surface, knowing the ultrasonic velocities in the coupling medium, is addressed. Conversely, we discuss a method to estimate the surface wave velocities on a given known profile.