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

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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 2017年4月11日 GMT-4 15:41
COMSOL Moderator

Hello Muyassar Ismaeel

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Posted: 8 years ago 2017年4月11日 GMT-4 08:24
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

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Posted: 8 years ago 2017年4月11日 GMT-4 15:41
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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