Definition of the acoustic potential by Helmholtz decomposition
* Presenting author
Abstract:
The definition of the acoustic quantities inside the fluid dynamic near field poses an open question in aeroacoustics. M.S. Howe addressed this issue by using the Helmholtz decomposition of the compressible velocity field by the curl of a vector potential and a gradient of the scalar potential. Based on this idea, we will present and verify Helmholtz decomposition to define the acoustic particle velocity for flows up to Mach 0.8. In doing so, the overflowed cavity example considers non-linear wave propagation effects based on a pre-computed compressible flow field by a direct numerical simulation resolving both the vertical and longitudinal structures. To conclude, we provide a detailed systematic analysis of Howe's definition of the near-field acoustic potential. The outcome of this study may help to derive future acoustic wave propagation models.