Question

The explicit under-relaxation method means that __________

(a) the changes are made before each iteration

(b) the changes are made before the iteration process

(c) the changes are made after the iteration process

(d) the changes are made after each iteration

I got this question in an interview.

My doubt stems from Under-Relaxation in section Discretization of the Source Term & Relaxation of Computational Fluid Dynamics

Answer 1

Correct answer is (c) the changes are made after the iteration process

The explanation is: Relaxation can be performed either after obtaining the solution of each iteration (explicitly) or before the process of iteration at each step (implicitly). Implicit methods are most commonly used.