During the past three decades, there has been a growing concern over the in crease in noise pollution that comes as a direct result of the increased volume of automobile traffic, high-speed trains, and larger aircraft. Additional sources of noise are commonly found in air handling equipment (such as fans and pro pellers) and a variety of machinery used in construction and manufacturing. A vast majority of these noise sources are the result of a given system's aero acoustic response, or sound generated by the interaction of a flow field with the given structure. While barriers are commonly...