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setting mass flow rate at inlet

Posted Jun 14, 2013, 4:53 p.m. EDT Computational Fluid Dynamics (CFD) Version 4.3b 2 Replies

Ahmed Suleiman
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Hi,
Model description

I have a 3D laminar air flow inside channel whose cross section is rectangle. for BC ,
1- the inlet , mass flow rate boundary is set (kg/s),
2- the outlet , zero pressure p=0 pa
3- the all other boundaries are symmetry.

My problem:

When I run it, I have a problem with convergence , then eventually failed to find the solution

Thanks

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2 Replies Last Post May 17, 2017, 5:18 p.m. EDT
COMSOL Moderator

Hello Ahmed Suleiman

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Александра Алиева
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Posted: 7 years ago May 17, 2017, 10:05 a.m. EDT
Updated: 7 years ago May 17, 2017, 10:06 a.m. EDT
Hi!
I know that it's the old post, but I'll try to ask, because I have the same problem here. Did you find the solution?
Hi! I know that it's the old post, but I'll try to ask, because I have the same problem here. Did you find the solution?
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 7 years ago May 17, 2017, 5:18 p.m. EDT
Hi

have you tried to either ramp up the flow, or add some more realistic initial conditions, as some average velocity and Poiseuille first estimate pressure drop across the channel as initial conditions ?

Starting a CFD model with "0" initial conditions and high inlet flow is tricky and not really "physical"

--
Good luck
Ivar
Hi have you tried to either ramp up the flow, or add some more realistic initial conditions, as some average velocity and Poiseuille first estimate pressure drop across the channel as initial conditions ? Starting a CFD model with "0" initial conditions and high inlet flow is tricky and not really "physical" -- Good luck Ivar

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