Absorbing Boundary Conditions

Absorbing boundary conditions for computational aeroacoustics (CAA) are reviewed. Commonly used absorbing zonal techniques, such as sponge layers and buffer zones, as well as perfectly matched layers (PML) are discussed. The basic ideas and central results of these methods are surveyed and summarized. Special attention will be given to the recently emerged PML technique and its application to CAA. Numerical examples are presented for PML in duct acoustics. A comparison of PML and non-PML absorbing boundary conditions will also be given.