Grid refinement study for three dimensional CFD model involving incompressible free surface flow and rotating object

Quantification of uncertainty in three dimensional Computational Fluid Dynamics (CFD) modelling is one of the challenging tasks demanding extensive computational resources. This paper deals with the grid refinement study for the three dimensional CFD model of a Dethridge water wheel as a rotating object and a free surface flow. Dethridge water wheel is a potential device to be used for hydropower generation in open channel flow. Grid refinement study is performed for the Dethridge water wheel model on three different grid resolutions and numerical uncertainty is quantified using the Grid Convergence Index (GCI). Key parameters relevant to the wheel performance are analysed and compared with the measured values. The small values of GCI indicate that the dependency of the results on the cell size is reduced.