Solved right, or the right equations

Verification and validation. Two different questions — whether the mathematics was done correctly, and whether the model matched reality — and the techniques that answer each one.

• 01Solved right, or the right equationsVerification asks whether the mathematics was done correctly; validation asks whether the model matched reality. They are different questions.
• 02The method of manufactured solutionsInventing an exact answer and forcing the equations to produce it is how a code is checked without an experiment.
• 03Where the theory stops and the mesher startsError estimates assume things about the mesh that real geometry rarely provides.