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How to define the boundary conditions for oscillatory flow in COMSOL?

Posted Mar 7, 2017, 6:42 p.m. EST Fluid & Heat, Acoustics & Vibrations, Heat Transfer & Phase Change, Computational Fluid Dynamics (CFD), Studies & Solvers 2 Replies

Muyassar Ismaeel
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Hi

I want to model an oscillatory flow passing fins inside a resonator.

I need to define both of the velocity and pressure boundary conditions at the inlet (x1) and the outlet (x2) of the computational domain.

The boundary conditions are given as:
p1 (x,t)= po cos (k' x1 ) cos⁡(ωt)

ua1= po/(ρm c) sin⁡(k' x1 )

p2 (x,t)= po cos⁡ (k' x2 ) cos⁡(ωt)

ua2= po/(ρm c) sin⁡(k' x2 )

∂T/∂x = 0 at x1 and x2

Could anybody assist me, please?

Thanks
Muyassar
2 Replies Last Post Apr 11, 2017, 3:41 p.m. EDT
COMSOL Moderator

Hello Muyassar Ismaeel

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Reza Ansari Shirvan
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Posted: 8 years ago Apr 11, 2017, 8:24 a.m. EDT
Hi Muyassar,

Define a waveform function first to form the sinusoidal part of the boundaries and then multiply it to the constant part of your boundary condition.

You can find the waveform function by right clicking on Definitions (under Component 1).
Then apply phase, amplitude and Angular frequency (to create proper sin/cos functions that you want)

Take a look at here:
www.comsol.dk/community/forums/cfd/thread/139992/

Best regards,
Reza

Hi Muyassar, Define a waveform function first to form the sinusoidal part of the boundaries and then multiply it to the constant part of your boundary condition. You can find the waveform function by right clicking on Definitions (under Component 1). Then apply phase, amplitude and Angular frequency (to create proper sin/cos functions that you want) Take a look at here: https://www.comsol.dk/community/forums/cfd/thread/139992/ Best regards, Reza
Muyassar Ismaeel
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Posted: 8 years ago Apr 11, 2017, 3:41 p.m. EDT
Hi Reza

Thank you very much.
I will try your suggestions..

regards
Muyassar
Hi Reza Thank you very much. I will try your suggestions.. regards Muyassar

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