Question

Consider the general discretized equation given by aP ΦP+∑F~NB(P)aF ΦF =0. Which of these statements is correct?

(a) When the value of ΦF is increased, the value of ΦP remains the same

(b) When the value of ΦF is increased, the value of ΦP increased

(c) When the value of ΦF is increased, the value of ΦP decreases

(d) When the value of ΦF is decreased, the value of ΦP decreases

This question was addressed to me in my homework.

This intriguing question originated from Diffusion Problem topic in section Diffusion Problem of Computational Fluid Dynamics

Answer 1

Right choice is (c) When the value of ΦF is increased, the value of ΦP decreases

Explanation: The value of ΦP varies with the variation of the values of ΦF. So, it will not remain the same. When the value of ΦF is increased, the value of ΦP decreases. This is the statement of the opposite signs rule taken physically.