July 7, 2020 at 4:08 pmPurdueMESubscriber
I have a simulation where I want to model a porous zone in steady state. When I set the zone to non-porous I get a solution which converges quickly. When I set the zone to a porous zone the continuity residual does not converge within a few thousand iterations. In my model I have 3 zones, two of which are non-porous. When I set the middle zone to be porous the issue arises.
I have a velocity inlet condition and a pressure outlet condition.
When I set the boundary condition at the inlet to be a pressure boundary condition the solution converges rapidly.
Any advice would be greatly appreciated.
July 7, 2020 at 5:07 pmRKAnsys Employee
You have mentioned that with pressure inlet you get convergence. Can you please be more specific on your question?
July 7, 2020 at 5:11 pmPurdueMESubscriber
I am simulating a phenomena where I know the inlet volumetric flow, which in this case I am converting to velocity.
I am wondering why there would be a difference in the convergence behavior, or how to address the lack of convergence for the continuity residual.
I am using the viscous flow model with default values for the solvers.
July 8, 2020 at 1:02 amKarthik RAdministrator
What are your solver settings? Are you using a Coupled Pseudo-Transient to solve this model? Also, which viscous model is this? Do you have turbulence here?
Can you share what your inlet pressure value is? Also, what velocity are you using?
July 8, 2020 at 4:08 pmPurdueMESubscriber
I think I found the answer digging through the manual. For anyone else following the thread I found the answer at the url:
https://www.afs.enea.it/project/neptunius/docs/fluent/html/ug/node233.htm#sec-porous-limitations under the section "Solution Strategies for Porous Media".
July 8, 2020 at 4:17 pmPurdueMESubscriber
But to answer your question I am using the following:
- Solver Settings
- . Pressure Based. Absolute Velocity, Steady, Planar (2D)
- Coupled Pseudo-Transient
- Viscous Model
- Solver Settings
July 8, 2020 at 4:18 pmPurdueMESubscriber
It seems that, following the advice of the manual, if I initialize the region with a pressure I achieve rapid convergence.
July 9, 2020 at 11:49 amKarthik RAdministrator
Perfect! Could you please mark your answer as 'Is Solution' to benefit others on the community?
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