Proble in the Simulation of a dead-end T-Junctionpipe using SimpleFoam-----PimpleFoam

Chrisstiapis · December 17, 2014, 16:59

Dear all,

I'm new to CFD and for academic reasons I have to simulate piping installations.
I'm trying now to simulate a dead-end T-Junction pipe. The figure below I think is helpful.

[/IMG]
The issue now is that when I try to simulate this in simpleFoam the residuals never converge and the pressure is oscillating.
When I use the pimpleFoam the simulation is aborted after some timesteps due to very high courant numbers.

I'm really in a loss.
I have tried various mesh densities but this doesn't seem to improve the situation.I'm also experimenting in laminar and again the same behaviour is observed.

It seems that there should be a trick with the dead-end region that I'm not aware of.
Here are the case files if someone wants to take a look at them

https://www.dropbox.com/sh/29os1zp95...97hjVW_Na?dl=0
https://www.dropbox.com/sh/q1e6rmpnl...XUdExe1pa?dl=0
https://www.dropbox.com/sh/jxqrl3iwk...6rXFJjuKa?dl=0

Thank u, in advance
Chris

taxalian · December 17, 2014, 17:38

Quote:

Originally Posted by Chrisstiapis

Dear all,

I'm new to CFD and for academic reasons I have to simulate piping installations.
I'm trying now to simulate a dead-end T-Junction pipe. The figure below I think is helpful.

[/IMG]
The issue now is that when I try to simulate this in simpleFoam the residuals never converge and the pressure is oscillating.
When I use the pimpleFoam the simulation is aborted after some timesteps due to very high courant numbers.

I'm really in a loss.
I have tried various mesh densities but this doesn't seem to improve the situation.I'm also experimenting in laminar and again the same behaviour is observed.

It seems that there should be a trick with the dead-end region that I'm not aware of.
Here are the case files if someone wants to take a look at them

https://www.dropbox.com/sh/29os1zp95...97hjVW_Na?dl=0
https://www.dropbox.com/sh/q1e6rmpnl...XUdExe1pa?dl=0
https://www.dropbox.com/sh/jxqrl3iwk...6rXFJjuKa?dl=0

Thank u, in advance
Chris

Hi Chris,
I would suggest to start your simulation with "icoFoam" solver which is suitable for laminar, isothermal and incompressible flows.

Chrisstiapis · December 19, 2014, 05:00

I used IcoFoam,
In this particular case where there is only one vertical outlet the icoFoam works, but when I use pimpleFoam in Laminar it crashes.
-- This seems weird to me

When i try to use a geometry with more vertical outlets then the simulation crashes even in pimpleFoam because of high courant numbers......

I really don't understand what is going on.
SimpleFoam never converges.

December 17, 2014, 16:59	Proble in the Simulation of a dead-end T-Junctionpipe using SimpleFoam-----PimpleFoam	#1
Chrisstiapis New Member Chris Stiapis Join Date: Mar 2014 Posts: 19 Rep Power: 12	Dear all, I'm new to CFD and for academic reasons I have to simulate piping installations. I'm trying now to simulate a dead-end T-Junction pipe. The figure below I think is helpful. [/IMG] The issue now is that when I try to simulate this in simpleFoam the residuals never converge and the pressure is oscillating. When I use the pimpleFoam the simulation is aborted after some timesteps due to very high courant numbers. I'm really in a loss. I have tried various mesh densities but this doesn't seem to improve the situation.I'm also experimenting in laminar and again the same behaviour is observed. It seems that there should be a trick with the dead-end region that I'm not aware of. Here are the case files if someone wants to take a look at them https://www.dropbox.com/sh/29os1zp95...97hjVW_Na?dl=0 https://www.dropbox.com/sh/q1e6rmpnl...XUdExe1pa?dl=0 https://www.dropbox.com/sh/jxqrl3iwk...6rXFJjuKa?dl=0 Thank u, in advance Chris

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December 19, 2014, 05:00		#3
Chrisstiapis New Member Chris Stiapis Join Date: Mar 2014 Posts: 19 Rep Power: 12	I used IcoFoam, In this particular case where there is only one vertical outlet the icoFoam works, but when I use pimpleFoam in Laminar it crashes. -- This seems weird to me When i try to use a geometry with more vertical outlets then the simulation crashes even in pimpleFoam because of high courant numbers...... I really don't understand what is going on. SimpleFoam never converges.