convergence criterion

Winston Gregorio

hi, i've asked this question on a previous thread, but its so far back that i dont think anyone will see it. I'm a third year student currently doing my 3rd year project and i'm using fluent to analyse fluid over a submerged submarine fin. now i'v manage to get some results from it, but its just a matter of interpreting them. i know this will sound really stupid. But what is the convergence criterion? I understand what the word means, but i dont know how it relates to CFD. Also, when iterating, a graph is plotted of the residuals against no of iterations which i am unsure about. Please, if anyone can help me leave a message