6. Discussion In the previous section, it has been demonstrated theWEM pro- vides a reasonably robust method for computing the propagation in a flow impedance tube. When used to educe the impedance of a liner, the values obtained are consistent with those found using a FEM to solve the propagation equation. Despite the limitations of the Myers boundary condition, the methodology has captured the reduction in SPL across the liner using impedance values which are consistent with those educed using more computationally demanding procedures in Refs. [11,26,14].