Hello. I'm using COMSOL for an acoustics project, and I have trouble setting up the PML to work perfectly.
My case: A rectangular room with totally absorbing ceiling. The room is simply a block, and I have added another block on top which simulates the ceiling as a PML boundary.
However, when simulating, the resonance frequencies are somewhat higher than the theoretical resonances. They clearly depend on the PML set-up. Theoretically I believe the resonance frequencies should be reduced when adding a resistive element (the PML).
I've tried both cartesian and spherical spreading for the PML, the spherical works best with the sphere centre placed a bit under the floor, but this is still not ideal.
Any suggestions? See attached screenshots.
My case: A rectangular room with totally absorbing ceiling. The room is simply a block, and I have added another block on top which simulates the ceiling as a PML boundary.
However, when simulating, the resonance frequencies are somewhat higher than the theoretical resonances. They clearly depend on the PML set-up. Theoretically I believe the resonance frequencies should be reduced when adding a resistive element (the PML).
I've tried both cartesian and spherical spreading for the PML, the spherical works best with the sphere centre placed a bit under the floor, but this is still not ideal.
Any suggestions? See attached screenshots.