Question

What does Richardson extrapolation do in finite difference schemes?

(a) Add the error estimate to the results of the finest grid

(b) Subtract the error estimate from the results of the finest grid

(c) Add the error estimate to the results of the current grid

(d) Subtract the error estimate from the results of the current grid

The question was asked in an interview.

My question is based upon Errors in Finite Difference Approximations topic in section Finite Difference Methods of Computational Fluid Dynamics

Answer 1

The correct option is (a) Add the error estimate to the results of the finest grid

For explanation: When we have the results of many grid arrangements ranging from coarse to fine. A solution which is more accurate than the solution of the finest grid can be obtained by adding the error estimate to the results of the finest grid available.