For the project Near-field Acoustical Holography - a new sensor concept for methods of active noise reduction, it is necessary to formulate the radiated sound power of a planar source in the transform domain. The transform representation is commonly derived by applying the Fourier transform to the inhomogeneous Helmholtz equation. After all, one ends up with Weyl’s identity, which is derived here first. Second, sound-power formulations based on Fourier transformed particle velocities and sound pressures are derived.
Steffen Ungnad (Thu,) studied this question.