# doubt in post processing

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 December 3, 2011, 00:45 doubt in post processing #1 New Member   murugesan Join Date: Aug 2011 Posts: 8 Rep Power: 6 Hi, I have a small question: during iterations I get the warning message "reversed flow in xxxx faces on pressure outlet". The number xxxx goes down with iterations. then the solution converges and there are still about 1000 faces in the outlet with reversed flow. If I continue the iterations the number keeps falling, and probably it will reach zero (no more warnings). What does this mean? Is the solution not really converged when FLUENT says so (according to the default residuals criteria)? IS the solution converged when finally there are no more faces with reversed flow or when this number stays constant? thanks

 December 3, 2011, 04:18 Hi #2 Senior Member   shoeb khan Join Date: Nov 2011 Posts: 179 Rep Power: 6 Hi may be i am wrong, but according to me Many times there is a reverse flow problem at the starting of the simulation. But as we proceed, the reverse flow problem vanishes and it doesn't comes back after a quite a long spam of iteration then surely i can say that the solution is converged. Correct me if i am wrong please. SHK

 December 3, 2011, 07:10 #3 New Member   kamran Join Date: Apr 2011 Posts: 17 Rep Power: 6 In every turbulent model we have some large eddies which may bring about Reversed Flow.That's something normal.

 December 3, 2011, 13:56 #4 Senior Member   shoeb khan Join Date: Nov 2011 Posts: 179 Rep Power: 6 No turbulence models doesn't create reverse flows it just depend on ur geometries u can switch on turbulence models when ur solution is converged hope that will help u shk

 December 4, 2011, 02:47 #5 New Member   kamran Join Date: Apr 2011 Posts: 17 Rep Power: 6 Model and geometry are both important.

 December 13, 2011, 03:13 #6 Member   Join Date: Mar 2009 Posts: 39 Rep Power: 8 Hi, According to my understanding, criterion for solution convergence and reverse flow are two different things. You can always check your solution is converged OR not by simulating for higher criterion of solution convergence. You can adjust related parameters in pressure-outlet BC if reverse flow is occurring and it is not desirable! Mehulkumar

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