Because I want to test the case, I can safely said that I'm not too concern about the prediction of seperation and the results in general, for the moment. Once I can confirm that all the schemes, the BC and the IC are wright, I'll proceed with a refine mesh. But right now, what it does on the residuals it decrease and then increase a bit for finally getting a 'plateau/stagnation' where the residuals stay basically the same iteration after iteration. The reason why I was asking if it could converge even though 4<y+<5 is that, I use the wall function 'nutUSpaldingWallFunction' for nut but didnt fix any 'maxIter' nor 'tolerance' parameters yet.