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January 23, 2024, 15:18 |
Convergence issue on a very simple case
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#1 |
New Member
Santi Parera
Join Date: Jul 2019
Location: BARCELONA
Posts: 26
Rep Power: 7 |
Hey foamers,
I'm not pretty new at OpenFOAM. I have worked on some cases of medium dificulty (non newtonian, turbulence, complex geometry, etc.) in the past. Now I want to work on a simple venturi on a pipe. But first of all, I have started just simulating water flow through a straight pipe. It is a straight pipe diam 50 mm and lenght 300 mm. Boundaries are: - U inlet (zeroGradient) outlet (fixedValue uniform 0 0 1) walls (noSlip) - p inlet (fixedValue uniform 0) outlet and walls (zeroGradient) Mesh is done by blockMesh macro to adapt well to cylinders (extended checkMesh is fully OK). Always in laminar condition, starting with 10 cPs, the simulation (simpleFoam) converges so well. Using final data as 0 and reducing the viscosity to 5 cPs, everything continues to be OK. Again, now with good data as 0, when I reduce viscosity to 1 cPs (water) the p residual starts to climb smoothly performing a pretty constant wave and it ends diverging... Does someone have any idea? Thanks. |
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January 24, 2024, 05:31 |
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#2 |
Senior Member
Join Date: Dec 2021
Posts: 237
Rep Power: 5 |
Hey!
Can you share the case? |
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January 24, 2024, 08:50 |
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#3 |
Senior Member
Troy Snyder
Join Date: Jul 2009
Location: Akron, OH
Posts: 220
Rep Power: 19 |
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January 26, 2024, 11:54 |
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#4 | |
New Member
Santi Parera
Join Date: Jul 2019
Location: BARCELONA
Posts: 26
Rep Power: 7 |
Quote:
Here you can see the .zip of the case: https://drive.google.com/file/d/1EVv...ew?usp=sharing As I said, pretty simple. I have done everything with a p residual set of 0.001. If I do it with normal 0.01 it becomes even worse. |
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March 23, 2024, 16:03 |
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#5 |
New Member
Santi Parera
Join Date: Jul 2019
Location: BARCELONA
Posts: 26
Rep Power: 7 |
Hi Troy,
As you said, turbulence model was required. With the straight pipe I have been able to solve it, but when I add just a seondary inlet orthogonal to that pipe, convergence problems appear again. In attached the full case already run: https://drive.google.com/file/d/1IYn...ew?usp=sharing |
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