  We derive the weak limit of a linear viscoacoustic model in an acoustic liner
that is a chamber connected to a periodic repetition of elongated chambers --
the Helmholtz resonators. As model we consider the time-harmonic and linearized
compressible Navier-Stokes equations for the acoustic velocity and pressure.
Following the approach in Schmidt et al., J. Math. Ind 8:15, 2018 for the
viscoacoustic transmission problem of multiperforated plates the viscosity is
scaled as $\delta^{4}$ with the period $\delta$ of the array of chambers and
the size of the necks as well as the wall thickness like $\delta^2$ such that
the viscous boundary layers are of the order of the size of the necks. Applying
the method of two-scale convergence we obtain with a stability assumption in
the limit $\delta \to 0$ that the acoustic pressure fulfills the Helmholz
equation with impedance boundary conditions. These boundary conditions depend
on the frequency, the length of the resonators and through the effective
Rayleigh conductivity -- that can be computed numerically -- on the shape of
their necks. We compare the limit model to semi-analytical models in the
literature.
