Modeling aeroacoustic excitations by subsonic wave packets in the Kirchhoff formalism

Abstract

The present work aims at linking the shape of a wave packet to its acoustic e ciency through numerical integration of the homogeneous Helmholtz equation in the Kirchho formalism. We shall consider the case of a bidimensional, rectangular domain where one side is a ected by a spatially evolving wave packet as a boundary condition with subsonic convection velocity. In the rst place, the numerical tool is validated by comparison with analytical developments available in literature. Then, an extension to more advanced forms of wave packet is approached. The appearance of a criterion for acoustic e ciency is discussed, as well as the need for a proper de nition regarding the acoustic energy of a wave packet and its radiated energy output.