These parameters are related to the interaction between the fluid and the solid phases in the material.
The open porosity and the static air flow resistivity are two examples of these parameters.
Read more about these acoustical parameters on the dedicated page.
These parameters are related to the solid phase of the
material. Studies of acoustical porous media are usually limited to small deformation vibrations these parameters thus reduced to the "elastical &
damping" ones (Young's moduli, Poisson's ratios, structural damping coefficients...).
Read more about these elastical parameters on the dedicated page.