Question

The area in the western face of a 2-D steady-state diffusion stencil (uniform) is _______________

(a) grid size in the x-direction

(b) grid size in the y-direction

(c) product of the grid sizes in the x and y-directions

(d) ratio of the grid sizes in the x and y-directions

This question was addressed to me in an online interview.

Question is taken from FVM for Multi-dimensional Steady State Diffusion in portion Diffusion Problem of Computational Fluid Dynamics

Answer 1

Right choice is (b) grid size in the y-direction

To elaborate: In the one-dimensional case, the area is taken to be unity. In the two-dimensional case, the area is the grid size in the perpendicular direction multiplied by unity. So, for area Ae=Aw=Δy and An=As=Δx.