[petsc-users] PetscFV types

[Pierre Seize]

So the difference between the two types is in DMPlexGetFaceFields : the 
upwind just takes the cell averaged (or cell centerd) states, and the 
least-squares use the gradient to reconstruct the states ?

Thanks

Pierre


On 18/09/20 12:24, Matthew Knepley wrote:
> On Fri, Sep 18, 2020 at 4:01 AM Pierre Seize <Pierre.Seize at onera.fr 
> <mailto:Pierre.Seize at onera.fr>> wrote:
>
>     Hello,
>
>     I do not understand what are the two available types for the PetscFV
>     object : "upwind" and "leastsquares", because to me those two
>     properties
>     describe different parts of the Finite Volume formulation. Could
>     someone
>     explain, or give me some references ?
>
>
> Sure. PetscFV is mostly an exercise for me to determine if the meshing 
> and data layout
> infrastructure below can support finite volume methods, so the FV 
> methods that it does support
> are rather rudimentary. My understanding of FV is quite limited. 
> "upwind" is just the naive, first
> order FV method with pointwise Riemann solves for each local face. I 
> called it upwind since we
> just update the state with the upwind data. I guess I could have 
> called it "gudonov" as well. The
> "leastsquares" uses a least-squares reconstruction of the state over 
> cell+neighboring cells (closure
> of the star of the faces) to try and achieve second-order where 
> possible. I guess I could have called
> this "reconstructed".
>
>   Thanks,
>
>      Matt
>
>     Thank you
>
>
>     Pierre Seize
>
>
>
> -- 
> What most experimenters take for granted before they begin their 
> experiments is infinitely more interesting than any results to which 
> their experiments lead.
> -- Norbert Wiener
>
> https://www.cse.buffalo.edu/~knepley/ 
> <http://www.cse.buffalo.edu/%7Eknepley/>

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