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Normal acceleration with phase angle?

Posted 10.09.2010, 14:03 GMT-4 5 Replies

Matt Donarski
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Hi,

I'm doing an acoustic simulation where I would like to have two surfaces driven with a normal acceleration, and I would like the surface accelerations to have different phase angles. Is this possible? I have tried using complex numbers (x+iy) for the normal acceleration magnitudes and I do get different solutions. I just want to confirm that this is the correct method for including an acceleration with a phase angle.

Thanks!
-Matt
5 Replies Last Post 19.09.2010, 04:59 GMT-4
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago 11.09.2010, 07:01 GMT-4
Hi

my first reaction is to say yes it's correct, but I havent tried it out, so a check should be considered.

Normally COMSOL uses the "phasor" approach for the postprocessing (and sometimes proposes the phase angle explicitely) when not, it's normally the complex representation that is expected.

My way, in such cases, is to build a simple model with just the items to check and run some simulations on them to see if it behaves as expected, when I cannot find an already prepared example (cannot remember any)

--
Good luck
Ivar
Hi my first reaction is to say yes it's correct, but I havent tried it out, so a check should be considered. Normally COMSOL uses the "phasor" approach for the postprocessing (and sometimes proposes the phase angle explicitely) when not, it's normally the complex representation that is expected. My way, in such cases, is to build a simple model with just the items to check and run some simulations on them to see if it behaves as expected, when I cannot find an already prepared example (cannot remember any) -- Good luck Ivar
Matt Donarski
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Posted: 1 decade ago 15.09.2010, 14:10 GMT-4
Thanks Ivar,

I did as you suggested. FYI- This method does produce the correct expected result.

-Matt
Thanks Ivar, I did as you suggested. FYI- This method does produce the correct expected result. -Matt
Fatemeh Sharifi
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Posted: 1 decade ago 18.09.2010, 05:07 GMT-4
Hi
My problem is somehow like yours. I need to insert initial phase angle to some of my pressure boundaries in comsol acoustic module. I want to know whether you find a way to insert phase angle in acoustic module. Please let me know.
Thanks

With best regards,
fatemeh sharifi
Hi My problem is somehow like yours. I need to insert initial phase angle to some of my pressure boundaries in comsol acoustic module. I want to know whether you find a way to insert phase angle in acoustic module. Please let me know. Thanks With best regards, fatemeh sharifi
Matt Donarski
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Posted: 1 decade ago 18.09.2010, 14:00 GMT-4
Hi Fatemeh,

Yes, you can insert a pressure phase angle on different boundaries. For pressure boundary conditions in the frequency domain set
P0 = Amplitude *( cos(angle*pi/180) + i * sin(angle*pi/180))

Where:
Amplitude = pressure source amplitude [Pa]
angle = phase angle [degrees]

Regards-

Matt
Hi Fatemeh, Yes, you can insert a pressure phase angle on different boundaries. For pressure boundary conditions in the frequency domain set P0 = Amplitude *( cos(angle*pi/180) + i * sin(angle*pi/180)) Where: Amplitude = pressure source amplitude [Pa] angle = phase angle [degrees] Regards- Matt
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago 19.09.2010, 04:59 GMT-4
Hi

or you use the equivalent exp() way.
For the postprocessing, use the "phasor" angle to get right phase value out (you can also do plots over the phase angle. Check the Forum for "phasor" and you doc

--
Good luck
Ivar
Hi or you use the equivalent exp() way. For the postprocessing, use the "phasor" angle to get right phase value out (you can also do plots over the phase angle. Check the Forum for "phasor" and you doc -- Good luck Ivar

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