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Paradox in parallel computations

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Old   October 4, 2007, 10:29
Default Paradox in parallel computations
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Vg
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Hi CFD users,

I am running a 3D simulation of a centrifugal pump in Fluent 6.2.16. First i used the MRF method and all the cases were simulated in a single machine. There were no convergence problems.

Recently we made a network cluster of four machines. The OS is Linux SUSE 10. I am novice in parallel simulations. I am running the previous simulations with SM method using the MRF as an initial solution in parallel mode. I partition the grid in a serial solver and then I read the cas/dat in the parallel solver.

Here is the strange: When I group all the interfaces in a single partition by activating the "encapsulated grid interface " in Partition panel (This is recommended by Fluent manual for non-conformal meshes), my solution is diverged in the parallel solver. When de-activate the "encapsulated grid interface" my solution converges!!! Can anyone know why this happens? Isn't it strange? Thank you in advance,

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Old   October 9, 2007, 12:09
Default Re: Paradox in parallel computations
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rj
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Yes, this may happen, because the encapsulation is causing very long partition interfaces, which is very bad for convergence.
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