RECENT MODELS FOR ACOUSTIC-WAVE PROPAGATI ON IN POROUS MATERIALS

The modelling of the interactions between porous structures and satura ting fluids has known new developments. D.L Johnson has given a rigoro us definition of tortuosity and has introduced a new parameter, the vi scous characteristic dimension. A thermal characterictic dimension can be defined in a similar way. For the case of elastic structures, the two compressional waves must be taken into account. A matrix formulati on is presented, which simplifies the modelling of stratified porous m aterials having an elastic structure.