Verification, validation, and uncertainty in computational fluids dynamicsThis article is one of a selection of papers published in this Special Issue on Hydrotechnical Engineering.

In this paper, we discuss issues in verification, validation, and uncertainty prediction in computational fluid dynamics (CFD). Mesh adaptation is used to perform the systematic grid refinement studies required for code and simulation verification. We demonstrate the method of manufactured solutions (MMS) for code verification. Examples of successful and failed validation show that reliable prediction can only occur with an appropriate mathematical model of physics along with accurate numerical solution of the differential equations. The paper emphasizes good CFD practices to achieve systematic verification and put validation studies on solid grounds. Finally, the sensitivity equation method (SEM) is used to cascade input data uncertainty through the CFD code for estimating the uncertainty of the flow response.