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Old   January 24, 2007, 13:00
Default Diffusion
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Can anyone explain the difference between normal diffusion and cross diffusion?

These terms occur in the STAR-CD methodology manual (chapter 4 discretisation practices) where it discusses how the diffusive fluxes are discretised. A two part expression is given, the first part represents normal diffusion between P and neighbouring cell-centred node N and the second part represents cross-diffusion.

My aim is to gain an understanding of how the diffusive fluxes are discretised in STAR.


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Old   January 29, 2007, 12:55
Default Re: Diffusion
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They break the diffusion term into a part that is treated implicitly (normal diffusion) and a part that is treated explicitly (cross diffusion). If the line connecting the centroids of adjacent cells is perpendicular to the face, then cross diffusion will be zero; otherwise not. See the book by Ferziger and Peric for more details.
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