Influence on the numerical uncertainty of a generic submarine model by changing the wall-normal distribution of the wall-bounded grid cells

MARIN is using Computational Fluid Dynamics (CFD) for engineering applications on daily practice. To establish the credibility of the results verification and validation is desired. As explained by Roache: Verification is a purely mathematical exercise that intends to show that we are “solving the equations right”, whereas Validation is a science/engineering activity that intends to show that we are “solving the right equations”.
This paper focuses only on verification of CFD simulations performed with MARIN’s viscous flow solver ReFRESCO. For this verification analysis the numerical uncertainty method of Eça and Hoekstra is used, which is based on grid refinement studies of geometrical similar grids. The numerical uncertainty of a CFD prediction has three components, i.e., the round-off error, the iterative error and the discretisation error.
The aim of this paper is to get a better understanding of the relation between the numerical uncertainty estimation and the wall-normal distribution of the wall-bounded grid cells, since earlier work by, e.g., showed unexpected trends in the order of convergence based on the discretisation error.
All simulations are performed for a generic submarine model which is described in the next section. Furthermore the programme of simulations is explained followed by the results and ending with conclusions.