Question

Which of these statements states the need for the normalization of the residual?

(a) Different variables result in different level of residuals

(b) Different variables result in the same level of residuals

(c) Different variables result in different residuals

(d) Different variables result in same residuals

This question was posed to me at a job interview.

Origin of the question is Relaxation topic in portion Discretization of the Source Term & Relaxation of Computational Fluid Dynamics

Answer 1

Right option is (a) Different variables result in different level of residuals

Explanation: When the influence of the sign of the residual can be ruled out by the absolute residual, the level of the absolute residual varies with the value of the flow variables. To overcome this problem, the residuals are normalized.