Non-orthognal correction for neutron diff

  • gianluca

    gianluca - 2010-12-19

    I am modifying OpenFVM to deal with the neutron diffusion equation. The equation consists of a second order elliptic operator, in a way identical to the viscous diffusion term in the momentum equation. I noticed that when I perform the non-orthogonal correction, the code "blows up" if I divide the cell-center gradient by the volume of the mesh (Vp). If I don't divide by it, everything seems to be fine, meaning I get convergence and the results "make sense" compared to a case where I do not apply any non-orthogonal correction.
    Any clues?

  • x-flow

    x-flow - 2010-12-19

    Non-orthogonal corrections tend to make the solution more unstable because it adds "weight" to the source term. With non-orthogonal corrections it might be necessary to reduce the time step significantly.


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