Grid Sensitivity Studies for Single and Multi-Step Ice Accretion using Unstructured Meshes

The effects of grid spacing and time step sizes have been studied on an unstructured grid for a NACA 0012 glaze ice case. The methodology involving the mesh generation, the flow field computation, the collection efficiency of the water droplets, and ice accretion is discussed, and the formulation is documented. The surface grid density and boundary layer resolution effects on the predicted ice shape are considered. Relevant parameters such as the surface pressure, skin friction distribution, droplet collection efficiency, and ice shape predictions are presented and compared for the various grids. The impact of the surface y+ is also discussed. Based on the comparison of the predicted ice shapes against measured shapes and the computational costs associated, recommendations for a suitable mesh size and surface resolution are made.