Question

Which value is predicted in the predictor step of the MacCormack’s technique?

(a) Variable at the average time-step

(b) Variable at the upcoming time-step

(c) Time derivative of the variable at the upcoming time-step

(d) Time derivative of the variable at the average time-step

The question was posed to me at a job interview.

Question is taken from Finite Difference Methods in division Finite Difference Methods of Computational Fluid Dynamics

Answer 1

Right option is (b) Variable at the upcoming time-step

Explanation: To get the derivative in the upcoming time-step for finding the time derivative of the variable at the average time, the variable at that time step is needed. This is the value which we intend to find using MacCormack’s technique. So, in the predictor step, the value of the variable at that time step is predicted.