sharonyue |
December 1, 2012 03:01 |
same geometry,structured and unstructured mesh,different behaviour.
1 Attachment(s)
Hi Foamers:
I use the same geometry but different mesh which one is structured and the other is unstructured simulating bubblecolumn via twoPhaseEulerFoam, the other things such as BCs,FVscheme is totally the same.
while running, the deltaT is getting smaller and smaller in unstructured mesh,but delta T is stable in structured mesh. I check the unstructured mesh is OK, and the quality is above 0.36.
can anybody explain this to me? thanks in advance.
Code:
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
Create time
Create mesh for time = 0
Reading g
Reading transportProperties
Calculating face flux field phi1
Calculating face flux field phi2
Reading field alpha1
Reading field p
Reading field k
Reading field epsilon
Calculating field nut2
Calculating field nuEff1
Calculating field nuEff2
Calculating field DDtU1 and DDtU2
Calculating field g.h
Selecting dragModel for phase 1: SchillerNaumann
Selecting dragModel for phase 2: SchillerNaumann
dragPhase is 1
Selecting viscosityModel Syamlal
Selecting conductivityModel HrenyaSinclair
Selecting radialModel SinclairJackson
Selecting granularPressureModel Lun
Selecting frictionalStressModel JohnsonJackson
Courant Number mean: 1.38889e-06 max: 0.0114746
PIMPLE: Operating solver in PISO mode
Starting time loop
Courant Number mean: 1.37514e-06 max: 0.011361
Max Ur Courant Number = 0.011361
deltaT = 0.00235294
Time = 0.00235294
MULES: Solving for alpha1
MULES: Solving for alpha1
Dispersed phase volume fraction = 0.400913 Min(alpha1) = 0 Max(alpha1) = 1
GAMG: Solving for p, Initial residual = 1, Final residual = 0.0863091, No Iterations 4
time step continuity errors : sum local = 1.06044e-05, global = -1.14961e-06, cumulative = -1.14961e-06
GAMG: Solving for p, Initial residual = 0.000385431, Final residual = 4.25161e-09, No Iterations 8
time step continuity errors : sum local = 2.34062e-08, global = -8.86366e-09, cumulative = -1.15847e-06
ExecutionTime = 1.83 s ClockTime = 2 s
Courant Number mean: 0.000961133 max: 0.281556
Max Ur Courant Number = 0.284771
deltaT = 0.0027451
Time = 0.00509804
MULES: Solving for alpha1
MULES: Solving for alpha1
Dispersed phase volume fraction = 0.400913 Min(alpha1) = -1.12164e-20 Max(alpha1) = 1
GAMG: Solving for p, Initial residual = 8.63083e-05, Final residual = 4.00274e-06, No Iterations 1
time step continuity errors : sum local = 2.73396e-05, global = 2.22315e-06, cumulative = 1.06468e-06
GAMG: Solving for p, Initial residual = 4.42412e-05, Final residual = 5.60681e-09, No Iterations 7
time step continuity errors : sum local = 4.22789e-08, global = 6.16051e-10, cumulative = 1.06529e-06
ExecutionTime = 3.15 s ClockTime = 3 s
Courant Number mean: 0.0017551 max: 0.699786
Max Ur Courant Number = 0.556128
deltaT = 0.00194902
Time = 0.00704706
MULES: Solving for alpha1
MULES: Solving for alpha1
Dispersed phase volume fraction = 0.400913 Min(alpha1) = -6.81353e-17 Max(alpha1) = 1
GAMG: Solving for p, Initial residual = 3.65894e-05, Final residual = 1.57627e-06, No Iterations 1
time step continuity errors : sum local = 5.16964e-06, global = -9.58478e-08, cumulative = 9.69446e-07
GAMG: Solving for p, Initial residual = 5.6711e-05, Final residual = 6.50899e-09, No Iterations 6
time step continuity errors : sum local = 2.37495e-08, global = -3.80727e-09, cumulative = 9.65639e-07
ExecutionTime = 4.44 s ClockTime = 5 s
Courant Number mean: 0.00167936 max: 1.02324
Max Ur Courant Number = 0.747501
deltaT = 1.99755e-06
Time = 0.00949938
MULES: Solving for alpha1
MULES: Solving for alpha1
Dispersed phase volume fraction = 0.400913 Min(alpha1) = -8.90338e-22 Max(alpha1) = 1
GAMG: Solving for p, Initial residual = 0.0481777, Final residual = 0.00240455, No Iterations 1
time step continuity errors : sum local = 7.55737e-07, global = -8.0092e-10, cumulative = 8.87419e-07
GAMG: Solving for p, Initial residual = 0.170165, Final residual = 5.99529e-09, No Iterations 14
time step continuity errors : sum local = 2.58254e-12, global = -1.71226e-13, cumulative = 8.87418e-07
ExecutionTime = 25.1 s ClockTime = 25 s
Courant Number mean: 0.000246545 max: 0.954781
Max Ur Courant Number = 0.715363
deltaT = 1.04607e-06
Time = 0.00950043
MULES: Solving for alpha1
MULES: Solving for alpha1
Dispersed phase volume fraction = 0.400913 Min(alpha1) = -8.90337e-22 Max(alpha1) = 1
GAMG: Solving for p, Initial residual = 0.0453175, Final residual = 0.00277426, No Iterations 1
time step continuity errors : sum local = 8.16799e-07, global = -3.74529e-10, cumulative = 8.87044e-07
GAMG: Solving for p, Initial residual = 0.112757, Final residual = 4.36559e-09, No Iterations 14
time step continuity errors : sum local = 1.57546e-12, global = -1.38487e-13, cumulative = 8.87044e-07
ExecutionTime = 26.55 s ClockTime = 27 s
Courant Number mean: 0.000191191 max: 0.775023
Max Ur Courant Number = 0.526832
deltaT = 6.74865e-07
Time = 0.0095011
MULES: Solving for alpha1
MULES: Solving for alpha1
Dispersed phase volume fraction = 0.400913 Min(alpha1) = -8.90337e-22 Max(alpha1) = 1
GAMG: Solving for p, Initial residual = 0.0344062, Final residual = 0.00217738, No Iterations 1
time step continuity errors : sum local = 7.2002e-07, global = -5.49242e-10, cumulative = 8.86494e-07
GAMG: Solving for p, Initial residual = 0.0678397, Final residual = 7.71205e-09, No Iterations 13
time step continuity errors : sum local = 2.89794e-12, global = -2.90138e-13, cumulative = 8.86494e-07
ExecutionTime = 28.17 s ClockTime = 28 s
Courant Number mean: 0.000169 max: 0.691341
Max Ur Courant Number = 0.421516
deltaT = 4.88083e-07
Time = 0.00950159
MULES: Solving for alpha1
MULES: Solving for alpha1
Dispersed phase volume fraction = 0.400913 Min(alpha1) = -8.90337e-22 Max(alpha1) = 1
GAMG: Solving for p, Initial residual = 0.0242849, Final residual = 0.00133999, No Iterations 1
time step continuity errors : sum local = 5.12642e-07, global = -7.3266e-10, cumulative = 8.85762e-07
GAMG: Solving for p, Initial residual = 0.0466661, Final residual = 6.45613e-09, No Iterations 13
time step continuity errors : sum local = 2.72667e-12, global = -2.42677e-13, cumulative = 8.85761e-07
ExecutionTime = 29.69 s ClockTime = 30 s
Courant Number mean: 0.00016667 max: 0.681466
Max Ur Courant Number = 0.389559
deltaT = 3.58113e-07
Time = 0.00950195
MULES: Solving for alpha1
MULES: Solving for alpha1
Dispersed phase volume fraction = 0.400913 Min(alpha1) = -8.90337e-22 Max(alpha1) = 1
GAMG: Solving for p, Initial residual = 0.0275894, Final residual = 0.00152494, No Iterations 1
time step continuity errors : sum local = 6.50407e-07, global = -7.86185e-10, cumulative = 8.84975e-07
GAMG: Solving for p, Initial residual = 0.048091, Final residual = 7.15538e-09, No Iterations 13
time step continuity errors : sum local = 3.39665e-12, global = -3.10169e-13, cumulative = 8.84975e-07
ExecutionTime = 31.21 s ClockTime = 32 s
Courant Number mean: 0.000177114 max: 0.742118
Max Ur Courant Number = 0.434414
deltaT = 2.41277e-07
Time = 0.00950219
MULES: Solving for alpha1
MULES: Solving for alpha1
Dispersed phase volume fraction = 0.400913 Min(alpha1) = -8.90336e-22 Max(alpha1) = 1
GAMG: Solving for p, Initial residual = 0.0434491, Final residual = 0.00265364, No Iterations 1
time step continuity errors : sum local = 1.17267e-06, global = -7.89578e-10, cumulative = 8.84185e-07
GAMG: Solving for p, Initial residual = 0.0916966, Final residual = 4.20824e-09, No Iterations 14
time step continuity errors : sum local = 2.22575e-12, global = -2.16475e-13, cumulative = 8.84185e-07
ExecutionTime = 32.73 s ClockTime = 33 s
Courant Number mean: 0.000201607 max: 0.927977
Max Ur Courant Number = 0.614956
deltaT = 1.30002e-07
Time = 0.00950232
MULES: Solving for alpha1
MULES: Solving for alpha1
Dispersed phase volume fraction = 0.400913 Min(alpha1) = -8.90336e-22 Max(alpha1) = 1
GAMG: Solving for p, Initial residual = 0.0523101, Final residual = 0.00307465, No Iterations 1
time step continuity errors : sum local = 1.1458e-06, global = -7.83281e-10, cumulative = 8.83402e-07
GAMG: Solving for p, Initial residual = 0.167959, Final residual = 6.72381e-09, No Iterations 14
time step continuity errors : sum local = 3.37666e-12, global = -1.97947e-13, cumulative = 8.83402e-07
ExecutionTime = 34.2 s ClockTime = 34 s
Courant Number mean: 0.000213776 max: 1.09291
Max Ur Courant Number = 0.801885
deltaT = 5.94748e-08
Time = 0.00950238
MULES: Solving for alpha1
MULES: Solving for alpha1
Dispersed phase volume fraction = 0.400913 Min(alpha1) = -8.90336e-22 Max(alpha1) = 1
GAMG: Solving for p, Initial residual = 0.0529512, Final residual = 0.00271119, No Iterations 1
time step continuity errors : sum local = 7.97202e-07, global = -7.88211e-10, cumulative = 8.82613e-07
GAMG: Solving for p, Initial residual = 0.213293, Final residual = 8.38933e-09, No Iterations 14
time step continuity errors : sum local = 3.56226e-12, global = -1.41309e-13, cumulative = 8.82613e-07
ExecutionTime = 35.67 s ClockTime = 36 s
Courant Number mean: 0.000203657 max: 1.09677
Max Ur Courant Number = 0.834422
deltaT = 2.71137e-08
Time = 0.0095024
MULES: Solving for alpha1
MULES: Solving for alpha1
Dispersed phase volume fraction = 0.400913 Min(alpha1) = -8.90336e-22 Max(alpha1) = 1
GAMG: Solving for p, Initial residual = 0.0456457, Final residual = 0.00239763, No Iterations 1
time step continuity errors : sum local = 6.07151e-07, global = -6.76636e-10, cumulative = 8.81937e-07
GAMG: Solving for p, Initial residual = 0.170025, Final residual = 7.23531e-09, No Iterations 14
time step continuity errors : sum local = 2.45147e-12, global = -1.08e-13, cumulative = 8.81936e-07
ExecutionTime = 37.23 s ClockTime = 38 s
Courant Number mean: 0.000167332 max: 0.906812
Max Ur Courant Number = 0.660191
deltaT = 1.495e-08
Time = 0.00950242
MULES: Solving for alpha1
MULES: Solving for alpha1
Dispersed phase volume fraction = 0.400913 Min(alpha1) = -8.90336e-22 Max(alpha1) = 1
GAMG: Solving for p, Initial residual = 0.0400672, Final residual = 0.00243865, No Iterations 1
time step continuity errors : sum local = 6.57129e-07, global = -5.7262e-10, cumulative = 8.81364e-07
GAMG: Solving for p, Initial residual = 0.109301, Final residual = 4.88328e-09, No Iterations 14
time step continuity errors : sum local = 1.58805e-12, global = -1.09765e-13, cumulative = 8.81364e-07
ExecutionTime = 38.74 s ClockTime = 39 s
Courant Number mean: 0.000143578 max: 0.769801
Max Ur Courant Number = 0.514251
deltaT = 9.7103e-09
Time = 0.00950243
--> FOAM Warning :
From function Time::operator++()
in file db/Time/Time.C at line 1024
Increased the timePrecision from 6 to 7 to distinguish between timeNames at time 0.00950242
MULES: Solving for alpha1
MULES: Solving for alpha1
Dispersed phase volume fraction = 0.400913 Min(alpha1) = -8.90336e-22 Max(alpha1) = 1
GAMG: Solving for p, Initial residual = 0.0301994, Final residual = 0.00188676, No Iterations 1
time step continuity errors : sum local = 5.87628e-07, global = -4.48811e-10, cumulative = 8.80915e-07
GAMG: Solving for p, Initial residual = 0.0676315, Final residual = 8.08041e-09, No Iterations 13
time step continuity errors : sum local = 2.84689e-12, global = -3.41917e-13, cumulative = 8.80915e-07
ExecutionTime = 40.17 s ClockTime = 40 s
Courant Number mean: 0.000133312 max: 0.69952
Max Ur Courant Number = 0.425703
deltaT = 6.94069e-09
Time = 0.009502436
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