Ultrasonic surface waves and Lamb waves in fluid saturated porous solids

The interactions of ultrasonic waves with a fluid/fluid-saturated porous solid interface and a fluid-saturated porous solid plate in a vacuum and in fluid have been studied. In the first case surface modes are generated and detected by using a periodically corrugated surface structure of a fluid-saturated porous solid; in the second case, the behavior of Lamb waves has been investigated theoretically and experimentally. Dispersion curves of Lamb modes in a fluid-saturated porous plate with sealed pores and free boundary are computed to illustrate the role played by the second longitudinal (or slow) wave and its influence on the Lamb-wave spectrum. As a result of the study, applications have been found using the surface-wave techniques and the Lamb-wave technique to evaluate fluid-saturated porous media and to detect the slow longitudinal wave