Ansys Employee
The y+ value is assigned prior to meshing, however it's also a function of velocity and cell height which is why it's used to estimate the near wall cell height. You then run the solver where it's calculated, and can amend the mesh to suit. It's defined in the User's Guide, and is used very badly by most people explaining meshing. You do need to resolve the near wall cell, but also the flow boundary layer AND far field flow gradients. Getting y+ in the recommended limits just means you got one layer of cells in the right place..... n