I am trying to solve the one dimensional conductive heat transfer in the media which is exposed to air flow at the very right wall.

The boundary condition on the right wall is:
-k*(dT/dx)=h(Ts-Tspace) [EQUATION 1]

Based on the useful note that Mr Malaspinas kindly put on your website; I’ve tried to write down this boundary in the lattice domain.

-k*[(4Ti-1-Ti-2-3Ti)/2*dx]=h(Ti-Tspace) [EQUATION 2]

I’ve got one question. In the model problem (1D), I have only two directional temperatures. I suppose that I have to only apply equation 2 on the left directional temperature, as the right one will be known after the steaming step. So if I assume that I number the right direction as 1 and the left direction as 2, I will get the EQUATION 2 IN LATTICE DOMAIN AS FOLLOW:
-k*[(4T(i-1,2)-T(i-2,2)-3T(i,2))/2*dx]=h(T(i,2)-Tspace) [EQUATION 3]

Please let me know if I stand corrected.

Many thanks.