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May 18, 2010, 18:07 |
solving pressure equation
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#1 |
Member
Pascal
Join Date: Jun 2009
Location: Montreal
Posts: 65
Rep Power: 16 |
Hi all,
I am simulating wake vortices in ground effect and I'm using the icoFOAM application. I would like to know why it solve twice for p at each time step. I have no error message or warning just the following output when I'm solving. Code:
Courant Number mean: 0.0258412 max: 0.99935 deltaT = 0.000909091 Time = 0.000909091 DILUPBiCG: Solving for Ux, Initial residual = 0.00117738, Final residual = 8.40907e-08, No Iterations 4 DILUPBiCG: Solving for Uy, Initial residual = 0.00100752, Final residual = 6.02822e-07, No Iterations 3 DICPCG: Solving for p, Initial residual = 0.360239, Final residual = 9.95302e-07, No Iterations 982 time step continuity errors : sum local = 1.82785e-10, global = 4.3745e-21, cumulative = 4.3745e-21 DICPCG: Solving for p, Initial residual = 0.00983221, Final residual = 9.57613e-07, No Iterations 872 time step continuity errors : sum local = 2.375e-10, global = -6.8944e-20, cumulative = -6.45695e-20 ExecutionTime = 40.92 s ClockTime = 42 s Thank you, Pascal |
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May 19, 2010, 02:30 |
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#2 |
Senior Member
Gijsbert Wierink
Join Date: Mar 2009
Posts: 383
Rep Power: 18 |
Hi Pascal,
"Solving for p ..." shows up twice because in icoFoam's standard setting the number of pressure corrections in the PISO loop is set to two. If you wish, you can change this at the bottom of the system/fvSolution file where it reads Code:
PISO { nCorrectors 2; nNonOrthogonalCorrectors 0; pRefCell 0; pRefValue 0; }
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Regards, Gijs |
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May 19, 2010, 03:33 |
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#3 |
Senior Member
Anton Kidess
Join Date: May 2009
Location: Germany
Posts: 1,377
Rep Power: 29 |
While your at it, you should do some reading on how PISO works in Ferziger/Peric or the original paper by Issa and Olivera...
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May 19, 2010, 18:48 |
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#4 |
Member
Pascal
Join Date: Jun 2009
Location: Montreal
Posts: 65
Rep Power: 16 |
Thank you for all the information
Pascal |
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solving pressure |
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