Analysis techniques for aeroacoustics: noise source identification

Aeroacoustic analysis is concerned with the problem of

sound source mechanism identification

. Let us consider for a moment what we mean by this, because, depending on the context, the same terminology can be interpreted differently. Two different contexts for the analysis of an aeroacoustic system, or indeed a fluid flow system in general, are: (1) the

kinematic

context; and, (2) the

dynamic

context.

When we are interested in kinematics, we are concerned with description of the space-time structure of a fluid flow, and perhaps with phenomenological explanations

vis-à-vis

our observation of that structure:

this vortical structure interacted with that one to produce this or that result

. Such kinematic descriptions will very often be with regard to some observable; in aeroacoustics that observable is the radiated sound field:

this vortical structure interacted with that one to produce this or that property of the sound field

.