{"id":159526,"date":"2021-06-16T07:02:05","date_gmt":"2021-06-16T07:02:05","guid":{"rendered":"\/forum\/forums\/topic\/fluent-problem-at-partition-boundary-in-parallel-simulation-using-vof-and-porous-media\/"},"modified":"2021-06-17T15:15:31","modified_gmt":"2021-06-17T15:15:31","slug":"fluent-problem-at-partition-boundary-in-parallel-simulation-using-vof-and-porous-media","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/fluent-problem-at-partition-boundary-in-parallel-simulation-using-vof-and-porous-media\/","title":{"rendered":"Fluent: Problem at partition boundary in parallel simulation using VOF and porous media"},"content":{"rendered":"
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Dear community,<\/p>\n

I have a problem in parallel simulation. I want to simulate fluid flow in a porous media representing a generic underground mine. Therefore, is set up the geometry and assign porous media. Other specifications of my model are:<\/p>\n

·        VOF model used.<\/p>\n

·        porous media with spatially varying porosity and permeability in the domain<\/p>\n

·        two-phase (air, water) flow with compressible liquid for both phase<\/p>\n

·        laminar flow conditions<\/p>\n

·        UDF with mass source term for air-phase <\/p>\n

·        14 Solver processes with activated hyperthreading, partition method X-Cartesian<\/p>\n

·        Ryzen 7 3700X processor<\/p>\n

The code works in serial however I must investigate physics in more detail to check plausibility of the results. Serial simulation is very slow, so I wanted to start a parallel calculation. I parallelize my UDF’s, and the mesh is partitioned. But at some point, the calculation gives incorrect results. At a partition interface the volume fraction of water vanishes ahead of the fully water-filled area. Before there was a significant VOF of water. Additionally, a high negative static pressure evolves at the partition interface (see pictures). In serial mode there is no problem at this point. <\/p>\n

Does anybody faced such a problem in the past and may explain the reason for these 'artefact' and how I remove it? So far, I think there is a problem in communication between the node processes or with the water surface at the partition interface. The problem occurs even if I deactivate all my UDF's. When changing the partiton method the problem occurs at a different location due to changed location of the partition interface.<\/p>\n

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\n\"vof_error.png\"
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