Question

I general, for all the steady-state diffusion problems, the discretized equation can be given as aPΦ P = ∑anbΦnb-S. For a one-dimensional problem, which of these is wrong?

(a) ∑anb =aT+aB

(b) ∑anb =aS+ aN

(c) ∑anb =aW+aE

(d) ∑anb =aP+aE

I had been asked this question in unit test.

My question is taken from FVM for Multi-dimensional Steady State Diffusion in chapter Diffusion Problem of Computational Fluid Dynamics

Answer 1

Correct choice is (d) ∑anb =aP+aE

For explanation: For a one-dimensional problem is x-direction, ∑anb =aW+aE. For a one-dimensional problem is y-direction, ∑anb =aS+ aN. For a one-dimensional problem is z-direction, ∑anb =aT+aB.