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Acoustic velocity

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Hello all,

I am looking for a definition of acoustic velocity implemented in Comsol (Pressure acoustic/frequency domain - no flow). I want to make sure that what I am getting is exactly what I need. The Acoustic Module User Guide does not seem to have that definition. I really hope that it is defined as:

(u_ac)_i=[-1/(2*pi*f*rho)]*[dp/dx_i] with f being a frequency associated with a particular mode.

Can anybody help?

Thanks

2 Replies Last Post 2013年7月24日 GMT-4 13:09
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Hello Oleksandr Barannyk

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Posted: 1 decade ago 2013年7月24日 GMT-4 12:36
I know this is an old post but if anybody else still wonders ...

Yes it is as you think it is (However make sure that you don't miss the imagery "i"). Which means that it is only valid in the inviscid case (which makes sense here).

You can look this up yourself: In the "Model Builder" top click on "Show" and there mark "Equation View".
Now you have the Equation View under "Pressure Acoustics" -> "Pressure Acoustics Model".
You can find all variable definitions there. In your example: acpr.vx = -(d(acpr.p_t,x)-acpr.qx)/(acpr.rho_c*acpr.iomega)
(and accordingly for acpr.vy and acpr.vz).

Hope this helps ...

I know this is an old post but if anybody else still wonders ... Yes it is as you think it is (However make sure that you don't miss the imagery "i"). Which means that it is only valid in the inviscid case (which makes sense here). You can look this up yourself: In the "Model Builder" top click on "Show" and there mark "Equation View". Now you have the Equation View under "Pressure Acoustics" -> "Pressure Acoustics Model". You can find all variable definitions there. In your example: acpr.vx = -(d(acpr.p_t,x)-acpr.qx)/(acpr.rho_c*acpr.iomega) (and accordingly for acpr.vy and acpr.vz). Hope this helps ...

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Posted: 1 decade ago 2013年7月24日 GMT-4 13:09
Thank you Dirk!
Thank you Dirk!

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