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PimpleFoam runs full length even after residuals converge! |
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#1 |
Member
Shafik Walakaka
Join Date: Oct 2017
Posts: 38
Rep Power: 8 ![]() |
Hi there,
I am wanting my pressure residuals to converge once it drops below 1e-6. However, even after the residuals drop below 1e-6, PimpleFoam Continues to iterate its outerncorrectors up till 200 iterations. Does anyone know why this is the case. Here is my fvSolution file: ************************************** solver PCG; preconditioner DIC; tolerance 1e-5; relTol 0; } p_rgh { solver PCG; preconditioner DIC; tolerance 1e-07; relTol 0.05; } p_rghFinal { $p_rgh; relTol 0; } U { solver smoothSolver; smoother symGaussSeidel; tolerance 1e-06; relTol 0; } } PIMPLE { momentumPredictor no; nOuterCorrectors 200; nCorrectors 2; nNonOrthogonalCorrectors 0; residualControl { p { tolerance 1e-6; relTol 0; } } } relaxationFactors { equations { ".*" 1; } } ********************************************** Here is a snippet of the log file (you can see Iteration 12 has definitely converged): *********************************************** PIMPLE: iteration 11 smoothSolver: Solving for alpha.water, Initial residual = 0.000240257, Final residual = 4.2394e-10, No Iterations 3 Phase-1 volume fraction = 0.518487 Min(alpha.water) = -5.21399e-05 Max(alpha.water) = 1.09024 MULES: Correcting alpha.water MULES: Correcting alpha.water Phase-1 volume fraction = 0.518487 Min(alpha.water) = -0.000149382 Max(alpha.water) = 1.08945 DICPCG: Solving for p_rgh, Initial residual = 4.67206e-07, Final residual = 8.61561e-08, No Iterations 3 time step continuity errors : sum local = 4.08652e-09, global = -3.18898e-10, cumulative = 0.000898511 DICPCG: Solving for p_rgh, Initial residual = 1.17071e-07, Final residual = 7.90011e-08, No Iterations 1 time step continuity errors : sum local = 3.74715e-09, global = -3.18966e-10, cumulative = 0.000898511 PIMPLE: iteration 12 smoothSolver: Solving for alpha.water, Initial residual = 0.000240257, Final residual = 4.23937e-10, No Iterations 3 Phase-1 volume fraction = 0.518487 Min(alpha.water) = -5.21399e-05 Max(alpha.water) = 1.09024 MULES: Correcting alpha.water MULES: Correcting alpha.water Phase-1 volume fraction = 0.518487 Min(alpha.water) = -0.000149382 Max(alpha.water) = 1.08945 DICPCG: Solving for p_rgh, Initial residual = 4.51662e-07, Final residual = 8.37249e-08, No Iterations 3 time step continuity errors : sum local = 3.9712e-09, global = -3.19133e-10, cumulative = 0.00089851 DICPCG: Solving for p_rgh, Initial residual = 1.15396e-07, Final residual = 7.70865e-08, No Iterations 1 time step continuity errors : sum local = 3.65634e-09, global = -3.19198e-10, cumulative = 0.00089851 ************************************************** *********** Kind regards Shafik Last edited by walakaka; February 28, 2018 at 14:02. |
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#2 | |
Member
Shafik Walakaka
Join Date: Oct 2017
Posts: 38
Rep Power: 8 ![]() |
Quote:
Can't seem to understand the explanation available! Regards Shafik |
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#3 |
Member
Ricky
Join Date: Jul 2014
Location: Germany
Posts: 78
Rep Power: 12 ![]() |
Hallo Shafik,
instead of setting the residual control for p, set the residual control for p_rgh, as interFoam solves for p_rgh instead of p. No Iterations 1 --> that you have pointed it out, is nothing but the number of iterations taken to solve p_rgh for the given/set tolerance in fvSolution. Pimple: iteration 12 --> is the number of outer corrections (nOuterCorrectors) in your case max 200. Have a look at this literature hope this helps! Regards, Ricky
__________________
If it is easy, then something is fishy! Last edited by kera; February 28, 2018 at 12:57. |
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#4 | |
Member
Shafik Walakaka
Join Date: Oct 2017
Posts: 38
Rep Power: 8 ![]() |
Quote:
Thanks alot for your help, and thanks for introducing the particular literature to me! My simulation works now and I will explore the book to further understand the PIMPLE algorithm. Regards Shafik |
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