Viscous fluids exhibits a boundary layer close to rigid walls whose
thickness depends on the variation in time. We regard acoustic waves
transported in a viscous fluid in perforated chamber. The size and the
distance of the holes and the thickness of the boundary layer in
comparison to the wave-length motivates a two-scale asymptotic
expansion. By matched asymptotic expansion and surface homogenisation
the near field solution is given by cell problems around the wall and
the far field solution by problems on the limit domain.