On the Analysis and Construction of Perfectly Matched Layers for the Linearized Euler Equations

We present a detailed analysis of a recently proposed perfectly matched layer (PML) method for the absorption of acoustic waves. The split set of equations is shown to be only weakly well-posed, and ill-posed under small low order perturbations. This analysis provides the explanation for the stability problems associated with the spilt eld formulation and illustrates why applying a lter has a stabilizing e ect. Utilizing recent results obtained within the context of electromagnetics, we develop strongly well-posed absorbing layers for the linearized Euler equations. The schemes are shown to be perfectly absorbing independent of frequency and angle of incidence of the wave in the case of a non-convecting mean ow. In the general case of a convecting mean ow, a number of techniques is combined to obtain a absorbing layers exhibiting PML-like behavior. The e cacy of the proposed absorbing layers is illustrated though computation of benchmark problems in aero-acoustics. 3