Question

Which of these changes should be made in the semi-discretized equation to get the fully discretized equation?

(a) Express the face values in terms of the neighbouring face values

(b) Express the face values in terms of the cell values

(c) Express the cell values in terms of the face values

(d) Express the cell values in terms of the neighbouring cell values

The question was posed to me in an international level competition.

This intriguing question comes from Transient Flows topic in portion Transient Flows of Computational Fluid Dynamics

Answer 1

Correct answer is (b) Express the face values in terms of the cell values

The explanation: While discretizing the transient term, the semi-discretized equation contains the values at the cell faces. If these face values are expressed in terms of the cell values, the complete discretized form of the equation can be obtained.