Convergence crtieria

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 April 3, 2007, 12:31 Hi I am trying to test SIMP #1 Member   Hoang-Lam Join Date: Mar 2009 Location: Lausanne, Switzerland Posts: 60 Rep Power: 10 Hi I am trying to test SIMPLEFOAM with a Bird-Carreau law and I have a very trivial question: I noticed that, when running the non linear computation, I have to specify the number of iterations a priori, (their number is being suggested by the proogramme itself). Is it possible to run the programme in such a way that the computation interrupts automatically as soon as convergence is reached ? (comvergence criterium). Thank you in davance, Lam

 April 4, 2007, 05:07 Oh, THANKS a lot Mark, for rep #2 Member   Hoang-Lam Join Date: Mar 2009 Location: Lausanne, Switzerland Posts: 60 Rep Power: 10 Oh, THANKS a lot Mark, for replying me! I am going give a go right now! Cheers, Lam

 April 5, 2007, 04:40 I guess I wasn't explicit enou #3 Senior Member   Mark Olesen Join Date: Mar 2009 Location: http://olesenm.github.io/ Posts: 810 Rep Power: 21 I guess I wasn't explicit enough. You can either solve the equation and ignore the return value: solve(UEqn() == -fvc::grad(p)); OR solve the equation and use the return value: eqnResidual = solve(UEqn() == -fvc::grad(p)).initialResidual(); but not both. It is also essential to capture the mass residual. ie. replace pEqn.solve(); with if (nonOrth == 0) { eqnResidual = pEqn().solve().initialResidual(); maxResidual = max(eqnResidual, maxResidual); } else { pEqn().solve(); } The residuals from the turbulence equation are not directly accessible, but this might change in OpenFOAM 1.4

 April 5, 2007, 06:46 It looks mostly reasonable exc #4 Senior Member   Mark Olesen Join Date: Mar 2009 Location: http://olesenm.github.io/ Posts: 810 Rep Power: 21 It looks mostly reasonable except you don't need this line twice. eqnResidual = solve(UEqn() == -fvc::grad(p)).initialResidual();

 April 5, 2007, 09:20 Hi again Mark, I had remove #5 Member   Hoang-Lam Join Date: Mar 2009 Location: Lausanne, Switzerland Posts: 60 Rep Power: 10 Hi again Mark, I had removed the line which is not needed as you said. And of course, I did the Allmake to update the simpleFoam.C file. I made a computation, but the result has not changed. You can take a look at my fvSolution file: *********************** solvers { p ICCG 1e-03 0.01; U BICCG 1e-03 0.1; k BICCG 1e-03 0.1; epsilon BICCG 1e-03 0.1; R BICCG 1e-03 0.1; nuTilda BICCG 1e-03 0.1; } *********************** I just want a 1e-03 solver tolerance. But the computation still stopps at the endtime (=4000 itrations). I just have a solution wich seems to not menage to reach the convergence. Can you give some advice to get it right? Thanks in advance, Lam

 April 5, 2007, 09:50 I don't wish to be impolite, b #6 Senior Member   Mark Olesen Join Date: Mar 2009 Location: http://olesenm.github.io/ Posts: 810 Rep Power: 21 I don't wish to be impolite, but re-check the original suggestion: # include "readSIMPLEControls.H" ... if (simple.found("convergence")) { ... } Check "readSIMPLEControls.H" file to see what is being read there and its relation to the following if (simple.found(..)) conditional. Again, I really don't wish to be impolite, but I really don't have enough time to help much more than I already did. Sorry but you need to do this alone (or keep some basic commercial support). /mark

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