  Evolution of cosmological perturbations is considered in the model with
dynamical dark energy which non-gravitationally interacts with dark matter. The
dark energy equation of state parameter (EoS) is varying in time and is
parameterized by its adiabatic sound speed. Such model of interacting dark
energy has advantages over model with constant EoS, because it avoids
non-adiabatic instabilities of dark energy at radiation dominated epoch for
certain types of interaction in dark sector. The stability conditions for
solutions of equations of dark energy perturbations were derived. The impact of
strength of additional interaction between dark components on the evolution of
density and velocity perturbations in them is analysed for quintessence and
phantom types of dark energy.
