In Workbench meshing, ‘Size Function’ refer to automatic refinement algorithms, that can be invoked to properly mesh domains based on their topology. Several options are listed: -Adaptive: should not be used for CFD meshes -Curvature: refine curved zones, based on a provided ‘Curvature Normal Angle’ -Proximity: populate small gaps with provided ‘Number Cells Across Gaps’ -Curvature & proximity: combine two previous algorithms -Uniform: domain is meshed with a constant size, refinement are only local ones For CFD meshes, activate ‘Curvature’ whenever curved areas exist in your model. You might add ‘Proximity’ if you have small gaps to be refined, but it may prove very costly in terms of meshing time. In this case you have three options: -Keep only global ‘Curvature’, and activate ‘Proximity’ for local sizings where needed -Keep only global ‘Curvature’, and create local ‘Fixed’ sizings with smaller size -Use ‘Fixed’ global size function and create local sizings to refine curved areas and gaps where needed