A note on sound radiation into a uniformly flowing medium

The influence of a uniform cross flow on the power output from an idealized mechanical source, namely a vibrating strip set in a coplanar rigid wall, is studied within the framework of linear acoustic theory, and the time-average power output is characterized by appropriate expansions (of exact integral representations), for both small and large wave length/strip width ratios, in the subsonic flow regime. Since boundary layers are ignored, the model source envisaged furnishes only a limited accounting of fluid-acoustical coupling effects.