  We consider the fully dynamic Biot-Allard model, which includes memory
effects. Convolution integrals in time model the history of the porous medium.
We use a series representation of the dynamic permeability in the frequency
domain to rewrite the equations in a coupled system without convolution
integrals, suitable for the design of efficient numerical approximation
schemes. The main result is the well-posedness of the system, proved by the
abstract theory of R. Picard for evolutionary problems.
