inletOutlet but still reverse flow at the outlet

Bana · December 30, 2015, 13:13

Hi everybody
I am simulating an incompressible swirl flow turbulent case with the inletOutlet boundary condition for U,k,omega and zero pressure at the outlet. But after simulation it still exists reverse flow at the outlet. I also tried pressureInletOutletVelocity for U at the outlet but it didn't work too. Below is my outlet settings.
Any suggestion would be appreciated.
U:
outlet
{
type inletOutlet;//pressureInletOutletVelocity;
inletValue uniform (0 0 0);
value uniform (0 0 0);
}
p:
outlet
{
type fixedValue;
value uniform 0;
}
Thanks in advance

Ardali · December 30, 2015, 14:53

Hi,
change your pressure outlet boundary to 'zeroGradient'
Probably our domain is small!
Ardalan

Bana · December 31, 2015, 05:19

Dear Ardalan
Thanks for your reply, but I have zeroGradient B.C. at inlet so if I put the same for outlet, will the problem be well defined?
Best regards

Ardali · December 31, 2015, 06:04

Why not?!
Define reference cell and reference value for pressure. It must work.
See my paper: LES and DES of Strongly Swirling Turbulent Flow through a Suddenly Expanding Circular Pipe

Ardalan

December 30, 2015, 13:13	inletOutlet but still reverse flow at the outlet	#1
Bana Member Mohammad Reza Join Date: Sep 2015 Posts: 44 Rep Power: 10	Hi everybody I am simulating an incompressible swirl flow turbulent case with the inletOutlet boundary condition for U,k,omega and zero pressure at the outlet. But after simulation it still exists reverse flow at the outlet. I also tried pressureInletOutletVelocity for U at the outlet but it didn't work too. Below is my outlet settings. Any suggestion would be appreciated. U: outlet { type inletOutlet;//pressureInletOutletVelocity; inletValue uniform (0 0 0); value uniform (0 0 0); } p: outlet { type fixedValue; value uniform 0; } Thanks in advance

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December 30, 2015, 14:53		#2
Ardali Member Ardalan Join Date: Jul 2012 Location: Atlanta, USA Posts: 77 Rep Power: 13	Hi, change your pressure outlet boundary to 'zeroGradient' Probably our domain is small! Ardalan

December 31, 2015, 05:19		#3
Bana Member Mohammad Reza Join Date: Sep 2015 Posts: 44 Rep Power: 10	Dear Ardalan Thanks for your reply, but I have zeroGradient B.C. at inlet so if I put the same for outlet, will the problem be well defined? Best regards

December 31, 2015, 06:04		#4
Ardali Member Ardalan Join Date: Jul 2012 Location: Atlanta, USA Posts: 77 Rep Power: 13	Why not?! Define reference cell and reference value for pressure. It must work. See my paper: LES and DES of Strongly Swirling Turbulent Flow through a Suddenly Expanding Circular Pipe Ardalan