Question

Why is the residual form of the discretized equations used?

(a) It increases the rate of convergence

(b) It increases the stability

(c) It increases the accuracy

(d) Numerical errors are less

I had been asked this question at a job interview.

Question is from Relaxation topic in portion Discretization of the Source Term & Relaxation of Computational Fluid Dynamics

Answer 1

The correct choice is (d) Numerical errors are less

For explanation: The residual form of the discretized equations are mathematically equivalent to the standard form. In this form, the numerical errors are less when the variations are small for large flow variable values.