Boundary treatment for the velocity divergence calculation #227
mattfalcone1997
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Hello, I think In the line
The underlying equation is
Thus, I think we have |
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Hi,
I am having a closer look at how the velocity divergence is computed in the boundary cells when$1+\alpha$ with the left of the diagonal ($f_{n+2} = f_n +(f_n - f_{n-1})=2f_n - f_{n-1}$ . Obviously, I may be looking at the wrong bits of the code altogether.
nclx=2
and how the compact difference stencil is modified. I am particularly interested in the left-hand side of eq. 20 in Laizet and Lamballais 2009. I assume it uses ghost cells, but I'm unsure how. Line 741 in schemes.f90 in the current master suggests that the diagonal atnxm
(ccx6(nxm)
) iscbx6(nxm)
) being 0, but I am not sure why. Also to make sure that I am correct, I believe the right-hand side (line 3893 of derive.f90 ) extrapolates the ghost value:Best wishes and hopefully my question makes sense!
Matthew
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