Comparison of nonreflecting boundary conditions as applied to an external oscillating source problem

A gasdynamic problem with an external source of acoustic oscillations is considered. This formulation corresponds to a simplified problem of sound suppression in a liner element. Conditions at the free boundary should generate the incoming wave prescribed and provide leaving of acoustic waves without reflection. Two kinds of nonreflecting boundary conditions-local and nonlocal-are constructed. The both approaches are tested on different options of the problem formulation.