Dispersive characteristics of flat longitudinal elastic waves extending in porous liquid-saturated medium with cavities

At first sight, many continuous media possess numerous micropores which contain or do not contain liquid. These pores are much less than the macroscopic sizes of medium, but they are bigger than nuclear or molecular ones. Such models of porous medium as soil model are widely usedin geophysics. Liquid distribution (oil, water) in soil is explained by this model. This model is also used in biology, in particular, to describe the penetration of liquid through plants, for example, wood. In recent years artificial porous materials which are widely applied in everyday life, in equipment and other areas of human activitieshave been created. The present work considers the distribution of flat longitudinal waves in porous liquid-saturated medium with cavities. It is supposed that the energy dissipation of a wave in the medium can be neglected. The behavior of linear waves in porous media with cavities is studied. It is known that in the porous medium (Biot's medium) two longitudinal waves can extend, one of them is slow and the other one is fast. In our problemthree longitudinal waves are extending: two waves do itlike in the Biot medium and the third one does it due to medium cavities. If the mediumhad neither pores, nor cavities, then one fast wave would extend. The study of linear wave’s behavior is conducted by receiving and analyzingthe dispersive equation, phase speed and group speed characterizing the wave energy transfer.The density of spectral frequency is considered to determinethe range of the dispersion degree.The work presents the formation and analysis of dispersive dependences for the considered system. Areas of strong and weak dispersion, areas of normal and abnormal dispersion at certainvalues of system parameters are found.