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Velocity field (or gradient of the pressure field) in the Kirchhoff-Helmholtz interface
Posted Aug 9, 2023, 7:12 a.m. EDT Acoustics & Vibrations, Results & Visualization Version 6.1 2 Replies
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Hello,
I was using the Kirchhoff-Helmholtz interface to compute the acoustic pressure field generated by a source. I just saw that a very few predefined quantity are given for this interface.
Especially, I don't see any velocity or intensity field. When computing the gradient of the pressure field over each dimension, it always gives me 0. Do you have an idea of why this appears to be always be zero? Is it in the theoretical framework of the interface? It works well with field generated from BEM!
Best, Tristan
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The Exterior Field calculation gives you the pressure directly from the integral, whereas in BEM the integral is used for setting up a matrix system. I have actually never had to evaluate the velocity in the exterior field, but in general a gradient being zero will occur when the element order or the pressure is too low. So there might be something related to that here.
-------------------René Christensen, PhD
Acculution ApS
www.acculution.com
info@acculution.com
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Hi,
Fllow up from the support:
The PA,K-H interface does not solve for a discretized pressure dependent variable therefore it is not possible to take the local spatial derivative of the pressure in the same way it is possible for FEM and conventional BEM models, however the result is computed at far lower computational cost. The discretization setting for the PA,K-H is used to determine the resolution of the geometry, i.e. curved surfaces.