[gtr84]

Hello everyone, this is my first question on this forum

i've made a simulatio of a stratified fluid in a rotating system of reference.
So i'm going to solve equation of motion using Shallow Water approximation.

the code is written in matlab using C grid
i've done also one using an unstaggered (A) grid

The problem is that code with c grid is unstable even though
cfl condition is satisfied (the scheme of integration is FTCS + LAX for
both cases).
With A grid code works as it's expected

in the attachment there are both codes (you can use word pad to
view)

can you tell me if there's any mistake?

[gtr84]

maybe CFL condition is different for C grid.


for an unstaggered grid is CFL<0.5 (in 2 dimension)

i've noticed that c grid code is stable for very little
courant numbers, like 0.01


does anyone know something more about this?

thanks