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Different flow structures obtained due to the number of processors and time-steps

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Old   January 9, 2021, 23:05
Default Different flow structures obtained due to the number of processors and time-steps
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victor
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Dear Foamers,

I am recently working on the wide-gap Taylor-Couette flow (eta=0.5), the Reynolds number is 475, the number of vortices is varying according to the number of processors and time-steps.

In the work of Razzak, they found the number of vortexes is 6 at Reynolds number is 475. (https://doi.org/10.1063/1.5125640)

However, in my study, the number of vortexes is 6 when using 280 processors, the number of vortexes is 8 when using 240 processors, the number of vortexes is 10 when using 360 processors. The OpenFOAM version is openfoam5.

The decompose method used here is scotch, similar results observed with simple and hierarchical methods to do decompose.

So my question is whether the decomposing method in OF is able to such a lower Reynolds number? Have you ever met such an issue that the flow structure is varying according to the number of processors and time-steps?

Maybe in turbulent flow, the numerical dissipation induced by the parallel decomposing will be less significant.

Thanks in advance.
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File Type: jpg Re475_360_35_streamline.jpg (47.2 KB, 13 views)
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