“…The first approach is the absorbing boundary condition (ABC) [52,4,69,53,29,85,11,64,63,56,66,11,65,14,57,97,28], which is a boundary condition enforced at an artificial boundary such that unwanted reflections from the boundary are significantly minimised. The second approach corresponds to extending the domain to an absorbing layer of finite thickness where the underlying equations are transformed such that waves decay rapidly in the layer [83,7,23,15,102,6,36,41,94,77,99,59,1,73,90,72]. In order for an absorbing layer to be effective the equations must be perfectly matched [35,67,23,15].…”