Question

Which of these methods can be used to evaluate the errors in convection-diffusion schemes?

(a) Using the exact solution of the source-free problem

(b) Using the exact solution of the source and diffusion-free problem

(c) Using the exact solution of the diffusion-free problem

(d) Using the first-order schemes

The question was posed to me in an online interview.

My question is from Convection-Diffusion Problems in division Convection-Diffusion Problems of Computational Fluid Dynamics

Answer 1

The correct option is (b) Using the exact solution of the source and diffusion-free problem

To explain I would say: To evaluate the errors, a simplified version of the problem where there is no source and diffusion is taken and further velocity and density fields are assumed to be constants. The exact solution of this problem is used for the analysis.