# LBM palabos, dx ,dx /= 1

Hi all ,

I’m using the palabos code with some modifications F_eq, Tao, Omega, I modified the distribution funcion with Cs, C and tao

``````double precision, parameter:: deltax = 1.00d0
double precision, parameter:: deltat = deltax**2.0d0
double precision, parameter:: c = deltax / deltat

v(0:8,0) = (/0.0d0,c,0.0d0,-c,0.0d0,c,-c,-c,c/)
v(0:8,1) = (/0.0d0,0.0d0,c,0.0d0,-c,c,c,-c,-c/)

omega = deltat / (( 3.0d0*nu + 0.50d0) * (deltat/(deltax**2.0d0)))
``````

fEq(y,x,i)= t(i) * rho(y,x) * (1.0d0 + (3.0d0uxy)/(c**2.0d0) + (4.50d0uxyuxy)/(c**4.0d0) - (1.50d0uSqr(y,x))/(c**2.0d0))

I want simulated the Palabos code with different values dx , dt.
Normal Code in palabos:
omega = 1.0d0 / (3.0d0*nu+0.5d0)

In the papabos units articles say that dt – dx^2. when I change this parametrer the code doesn’t work.
some people calculated dx = L/ N , where L = lengh caracterictic and N number of node in the lengn… ok.

the problem is if I need to modify the stream rutine as is as in Palabos code that dx = 1 = dt =1

I need to modify the stream when the dx =dt=c /=1 ?

example palabos code stream rutine:

right direction
f(:,2:xDim,1) = f(:,1:xDim-1,1)
up direction
f(2:yDim,:,2) = f(1:yDim-1,:,2)
left direction
f(:,1:xDim-1,3) = f(:,2:xDim,3) and others direction…

thank everyone