# nonuniform mesh strucure

Hello everyone,

I tried to generete nonuniform mesh in lattice boltzmann.

My basic articles are:

1. He, X., Luo, L.-S., Dembo, M., Some Progress in Lattice Boltzmann Method. Part I. Nonuniform Mesh Grids, Journal of Computational Physics, 129, 1996, pp.357-363

2. He, X., Luo, L.-S., Dembo, M., Some progress in the lattice Boltzmann method: Reynolds number enhancement in Simulations, Journal of Physics A, Vol. 239, 1997, pp. 276-285.

In these articles; two interpolation scheme are used: First, second-order upwind interpolation is used in the interior channel (channel floe is studied in this article), second, second order central difference interpolation is applied to the mesh grids next to the boundaries.

Please, give me any detail about second order interpolation and central difference interpolation.

daralcan

I think some people in phorum interested and studied about nonuniform lattice mesh structure. Can you share experiment about LBM nonuniform mesh structure?

Dear All,

I looked the second -order upwind schema and second order central difference schema. and I understand their.

But, I found strange using central differencing in BC. Central differencing formula is (T is variable)

d^2t/dx^2=(T(i+1)-2T(i)+T(i-1))/dx^2

where T is variable, dx is distance between two nodes.

Therefore, i node is between two nodes, so where can I define in boudary? Or Should I define bc nodes between two nodes?