Are you using simple bounce back in your code for the boundary condition? I think that doesn’t work…
There is a paper by F.Dubois and P. Lallemand “On Lattice Boltzmann scheme, finite volumes and boundary conditions” in which it is described how to implement boundary condition. Actually it is a bit odd to me that simple bounce back doesn’t give the right results(indeed it doesn’t converge in my code).
the FDLBM part of my code is woking very well and giving good results.
but FVLBM part of my code is not giving a good result.
also FVLBM part of my code is only working with uniform squar grid( simplist grid)
you can compile my code using gcc compiler
actually I’m using Mingw under windows.
“Finite volume scheme for the lattice Boltzmann method on unstructured meshes” “Finite-volume lattice Boltzmann schemes in two and three dimensions”
in the up mentioned papers it written
"In all the computations we present in this paper, the update
of the (fi) at boundary nodes is similar to that for interior
nodes except at the boundary the corresponding covolumes
I think it means you can treat eatch (fi) normally (as FDLBM). after that in the boundary the change in volume contribution
and the source term witch should appear because the covolumes are not complete(see the figures in the papers)
should give us the correct boundary.
better read the papers up mentioned.
also I will read your paper then we can discuss.
in FVLBM the stream (“flux” as it is known in finite volume method) can be calculated using contribution of the neighbor cells. No need for directions.
For more information Read the two papers up mentioned.
But in curvilinear grid I don’t know how to do streaming.
You can read this paper for curvilinear grid. “Explicit finite-difference lattice Boltzmann method for curvilinear coordinates”
I think i read a paper that said Succi et.al work on FVLBM and they cant develop it and cant get a good result, after that, He et.al and Doolen, Mei, Shu, and le shi lu work on FDLBM, they said FDLBM could get better result, in meshless approaches and complex geometry.
I’ll try to find that paper and say you better.