NONLINEAR-INTERACTION OF ACOUSTIC-WAVES IN A NONUNIFORM FLUID-FLOW

The parametric radiation of difference-frequency sound generated by th e nonlinear interaction of pump waves in the presence of a compact non uniform fluid flow is investigated. It is established that a nonunifor m flow can induce additional side lobes in the radiation pattern. It i s shown that the amplitude of the new lobes can be comparable with the principal maximum if the flow contains spatial structures of sufficie ntly small scale in comparison with its geometrical dimensions.