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Wrong computation of acoustic pressure

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10 years 7 months ago - 10 years 7 months ago #7664 by Bryk
Hello

I have some troubles with the operator DYNA_LINE_HARM used in the computation of the Green's function in a room : it gives a good module/gain but a wrong phase.
I calculate the pressure generated at one point by a source in an rectangular room with rigid walls.
In my simulation the source is a cube with a speed affected to the surface ( and the length of the cube is small in comparison with the smallest lengthwave of the study so that the source may be consider as a point source).
In the' last step I normalize the pressure by the strength of the source in order to obtain the Green's function, with is compared to the analytic Green's function calculated thanks to matlab.
In the attachment you see the comparison between modules and phases of both Green's functions. The module from code_aster is right but the phase isn't :
it has a constant value of pi/2 whereas there should be phase jumps at resonances.

Anyone has an idea on how resolve this problem ?

You will find the mesh and command files in the attachment.
Last edit: 10 years 7 months ago by Bryk.
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10 years 7 months ago #7665 by Bryk

py.bryk wrote: Hello

I have some troubles with the operator DYNA_LINE_HARM used in the computation of the Green's function in a room : it gives a good module/gain but a wrong phase.
I calculate the pressure generated at one point by a source in an rectangular room with rigid walls.
In my simulation the source is a cube with a speed affected to the surface ( and the length of the cube is small in comparison with the smallest lengthwave of the study so that the source may be consider as a point source).
In the' last step I normalize the pressure by the strength of the source in order to obtain the Green's function, with is compared to the analytic Green's function calculated thanks to matlab.
In the attachment you see the comparison between modules and phases of both Green's functions. The module from code_aster is right but the phase isn't :
it has a constant value of pi/2 whereas there should be phase jumps at resonances.

Anyone has an idea on how resolve this problem ?

You will find the mesh and command files in the attachment.

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