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Nonlinear acoustic boundary impedance coupled to a linear acoustic volume

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Hi,

I am modeling a room in which the acoustics is assumed to be linear, and a nonlinear impedance (pressure or velocity dependent resistance) defining one of the boundary conditions. I am only looking for stationary solutions and I want to repeat this process for multiple frequencies, so I am using the Pressure Acoustics Frequency Domain solver.

The procedure I have in mind is the following iterative loop 1) initial guess in the acoustic pressure or velocity at the boundary of interest

2) calculation of the resistance (so impedance) according to the pressure or velocity value 3) solving 3D Helmholtz equation in the volume (using the calculated impedance as boundary condition) using FEM 4) extract the pressure or velocity at the boundary of interest from the 3D simulation results

Steps 2-3-4 would be repeated until convergence.

Is it possible to automatize this procedure directly in Comsol or do I need to couple Comsol with a Matlab (or similar) routine ?

Thanks in advance for the help


1 Reply Last Post Oct 10, 2020, 8:30 p.m. EDT
Dave Greve Certified Consultant

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Posted: 4 years ago Oct 10, 2020, 8:30 p.m. EDT

Most entries in the Settings window can take functions and not just numbers. So for the Impedance boundary condition, you can enter (for exampe) for the impedance

1.2[kg/m^3]343[m/s](p/1[Pa])

Is this the sort of nonlinear boundary condition you are after??

Most entries in the Settings window can take functions and not just numbers. So for the Impedance boundary condition, you can enter (for exampe) for the impedance 1.2[kg/m^3]*343[m/s]*(p/1[Pa]) Is this the sort of nonlinear boundary condition you are after??

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