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DPMFoam Overestimates Turbulent Dissipation

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Old   April 28, 2020, 06:55
Default DPMFoam Overestimates Turbulent Dissipation
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Sereff
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Hello everyone,

I was trying to evaluate the turbulence modulation of particles in boundary flow. Eveything runs smoothly for pimpleFoam and DPMFoam and I was able to get some interesting result. But then I tried to compare the result between pimpleFoam and DPMFoam without particle injection ( "active", "coupled", "transient" all set to "false;" in kinematicCloudProperties) just to prove the modulation was indeed due to the particle injection instead of different solver, thus making my concludion more robust. But I failed to do so. It seems that even without the particle injection, the turbulence in DPMFoam simulation was dissipated much faster than the turbulence in pimpleFoam.

Does anyone have some ideas? Thanks in advance for any suggestion.



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Old   April 28, 2020, 11:30
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could you please refer to the link at the bottom, if possible?

thanks.
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Old   May 5, 2020, 07:58
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after some digging. it seems to be caused by line 9, which increases the robustness of the solver while introducing extra diffusivity, of pEqn.H from DPMFoam:
Code:
    surfaceScalarField phiHbyA
    (
        "phiHbyA",
        (
           fvc::flux(HbyA)
         + alphacf*rAUcf*fvc::ddtCorr(Uc, phic) // <------- THIS LINE!
        )
    );
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