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Divergence problem in interpasechangefoam

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Old   March 21, 2014, 06:55
Default Divergence problem in interpasechangefoam
  #1
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Baris (Heewa)
Join Date: Jan 2013
Location: Japan
Posts: 130
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Hi to all,

I am trying to simulate cavitation inside of nozzle. It is turbulent flow, used RNG k-epsilon turbulence model. My nozzle shape is attached. Upside is inlet (wider one) down side is outlet. I am using interphasechangeFoam ver2.1.1. I have just done following modification in U.Eqn to decrease the calculate nut as indicated in the paper of Coutier Delgosha (2003).

Code:
 dimensionedScalar rhoUnit("rhoUnit", dimDensity, 1.0);

   surfaceScalarField muEff
    (
        "muEff",
        twoPhaseProperties->muf()
      + fvc::interpolate((Foam::pow((0.017-rho/rhoUnit),5)/Foam::pow((0.017-998),5)*(998-0.017)+ 0.017)*rho*turbulence->nut())
    );
I set the my BCs:

0/U
inlet ==> FixedValue
HTML Code:
outlet= intletOutlet and tried pressureInletOutletVelocity;
0/p_rgh
HTML Code:
inlet ==> zeroGradient
Outlet==> fixedValues ==>1e5, 1e4...0 (gradully decreased until 0)
and also for outlet i tried: fixedMeanValue
0/k-epsilon
HTML Code:
inlet ==>fixedValue
outlet ==> tried fixedValue and inletOutlet
wall ==>tried epsilonWallFunction/kqRWallFunction and zerogradient
0/nut
HTML Code:
inlet/outlet ==>calculated
wall==>nutkWallFunction
fvschemes
HTML Code:
divSchemes
div(rhoPhi,U) Gauss linear;
div(phi,epsilon) Gauss upwind;
div(phi,k) Gauss upwind;
div(phi,alpha) Gauss vanLeer;
div(phirb,alpha) Gauss interfaceCompression;

laplacianSchemes
{
default Gauss linear corrected;
}
snGradSchemes
{
default none;
snGrad(pd) limited 0.5;
snGrad(rho) limited 0.5;
snGrad(alpha1) limited 0.5;
}

fluxRequired
{
default none;
p_rgh;
pcorr;
alpha1;
}
fv.solution==>everything is same with tutorial only added:
HTML Code:
relaxationFactors
{
fields
{
}
equations
{
"U.*" 0.7;
"k.*" 0.5;
"epsilon.*" 0.5;
"p_rgh.*" 0.3;
}
==>>maxCo 0.5; I set deltaT as 10-7, 10-8.

Although i tried different BCS as indicated above always deltaT reached very low valuse and gave divergence floating point error as follows:

HTML Code:
GAMG:  Solving for p_rgh, Initial residual = 9.10213e-09, Final residual = 9.10213e-09, No Iterations 0
GAMG:  Solving for p_rgh, Initial residual = 9.10213e-09, Final residual = 9.10213e-09, No Iterations 0
time step continuity errors : sum local = 2.80061e+06, global = -4.94029e-10, cumulative = 0.00804153
GAMG:  Solving for p_rgh, Initial residual = 1.20034e-08, Final residual = 9.50047e-10, No Iterations 1
GAMGPCG:  Solving for p_rgh, Initial residual = 4.32284e-15, Final residual = 4.32284e-15, No Iterations 0
time step continuity errors : sum local = 994878, global = -2.11248e-10, cumulative = 0.00804153
PIMPLE: not converged within 50 iterations
ExecutionTime = 1974.23 s  ClockTime = 2002 s

Courant Number mean: 6.58573e+06 max: 2.47105e+13
deltaT = 2.17834e-30
--> FOAM Warning : 
    From function Time::operator++()
    in file db/Time/Time.C at line 1010
    Increased the timePrecision from 8 to 9 to distinguish between timeNames at time 6.97175e-05
Time = 6.97175051e-05

[11] #0  Foam::error::printStack(Foam::Ostream&)[3] #0  Foam::error::printStack(Foam::Ostream&)[7] #0  Foam::error::printStack(Foam::Ostream&)[6] #0  Foam::error::printStack(Foam::Ostream&)[10] #0  Foam::error::printStack(Foam::Ostream&)[9] #0  Foam::error::printStack(Foam::Ostream&) in "/opt/openfoam211/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
[3] #1  Foam::sigFpe::sigHandler(int)[2] #0  Foam::error::printStack(Foam::Ostream&) in "/opt/openfoam211/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
[7] #1  Foam::sigFpe::sigHandler(int) in "/opt/openfoam211/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
[11] #1  Foam::sigFpe::sigHandler(int)[4] #0  Foam::error::printStack(Foam::Ostream&)[5] #0  Foam::error::printStack(Foam::Ostream&) in "/opt/openfoam211/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
[9] #1  Foam::sigFpe::sigHandler(int) in "/opt/openfoam211/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
[10] #1  Foam::sigFpe::sigHandler(int) in "/opt/openfoam211/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
[7] #2   in "/opt/openfoam211/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
[2] #1  Foam::sigFpe::sigHandler(int) in "/opt/openfoam211/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
[3] #2  [0] #0  Foam::error::printStack(Foam::Ostream&)[1] #0  Foam::error::printStack(Foam::Ostream&) in "/opt/openfoam211/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
[4] #1  Foam::sigFpe::sigHandler(int) in "/opt/openfoam211/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
[5] #1  Foam::sigFpe::sigHandler(int) in "/opt/openfoam211/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
[9] #2   in "/opt/openfoam211/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
[11] #2   in "/lib/libc.so.6"
[3] #3   in "/opt/openfoam211/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
[10] #2  [8] #0  Foam::error::printStack(Foam::Ostream&) in "/lib/libc.so.6"
[7] #3   in "/opt/openfoam211/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
[6] #1  Foam::sigFpe::sigHandler(int) in "/lib/libc.so.6"
[11] #3   in "/opt/openfoam211/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
[2] #2   in "/lib/libc.so.6"
[9] #3   in "/opt/openfoam211/platforms/linux64GccDPOpt/lib/libO in "/opt/openfoam211/platforms/penFOAM.so"
[0] #1  linux64GccDPOpt/lib/libOpenFOAM.so"
Foam::sigFpe::sigHandler(int)[1] #1  Foam::sigFpe::sigHandler(int)
 in "/lib/libc.so.6"
[10] #3   in "/opt/openfoam211/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
[5] #2  
 in "/opt/openfoam211/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
[4] #2  

 in "/opt/openfoam211/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
[8] #1  Foam::sigFpe::sigHandler(int) in "/lib/libc.so.6"
[2] #3  
[7]  in "/home/yusuke/OpenFOAM/yusuke-2.1.1/platforms/linux64GccDPOpt/bin/RNGinterPhaseChangeFoam"
[7] #4  [3]  in "/home/yusuke/OpenFOAM/yusuke-2.1.1/platforms/linux64GccDPOpt/bin/RNGinterPhaseChangeFoam"
[3] #4  [11]  in "/home/yusuke/OpenFOAM/yusuke-2.1.1/platforms/linux64GccDPOpt/bin/RNGinterPhaseChangeFoam"
[11] #4   in "/lib/libc.so.6"
[5] #3   in "/opt/openfoam211/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
[6] #2   in "/opt/openfoam211/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
[1] #2   in "/lib/ in "/opt/openfoam211/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
[0] #2  libc.so.6"
[4] #3  

[10]  in "/home/yusuke/OpenFOAM/yusuke-2.1.1/platforms/linux64GccDPOpt/bin/RNGinterPhaseChangeFoam"
[10] #4  
 in "/lib/libc.so.6"
[1] #3  
 in "/opt/openfoam211/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
[8] #2   in "/lib/libc.so.6"
[0] #3  [2]  in "/home/yusuke/OpenFOAM/yusuke-2.1.1/platforms/linux64GccDPOpt/bin/RNGinterPhaseChangeFoam"
[2] #4  [11]  in "/home/yusuke/OpenFOAM/yusuke-2.1.1/platforms/linux64GccDPOpt/bin/RNGinterPhaseChangeFoam"
[11] #5  [9]  in "/home/yusuke/OpenFOAM/yusuke-2.1.1/platforms/linux64GccDPOpt/bin/RNGinterPhaseChangeFoam"
[9] #4  
 in "/lib/libc.so.6"
[6] #3  [3]  in "/home/yusuke/OpenFOAM/yusuke-2.1.1/platforms/linux64GccDPOpt/bin/RNGinterPhaseChangeFoam"
[3] #5  
[4]  in "/home/yusuke/OpenFOAM/yusuke-2.1.1/platforms/linux64GccDPOpt/bin/RNGinterPhaseChangeFoam"
[4] #4  [7]  in "/home/yusuke/OpenFOAM/yusuke-2.1.1/platforms/linux64GccDPOpt/bin/RNGinterPhaseChangeFoam"
[7] #5   in "/lib/libc.so.6"
[8] #3  

[5]  in "/home/yusuke/OpenFOAM/yusuke-2.1.1/platforms/linux64GccDPOpt/bin/RNGinterPhaseChangeFoam"
[5] #4  
[9]  in "/home/yusuke/OpenFOAM/yusuke-2.1.1/platforms/linux64GccDPOpt/bin/RNGinterPhaseChangeFoam"
[9] #5  [11]  in "/home/yusuke/OpenFOAM/yusuke-2.1.1/platforms/linux64GccDPOpt/bin/RNGinterPhaseChangeFoam"
[11] #6  __libc_start_main[0]  in "/home/yusuke/OpenFOAM/yusuke-2.1.1/platforms/linux64GccDPOpt/bin/RNGinterPhaseChangeFoam"
[0] #4  [1]  in "/home/yusuke/OpenFOAM/yusuke-2.1[3]  in "/home/yusuke/OpenFOAM/yusuke.1/platforms/linux64GccDPOpt/bin/RNGinterP-2.1.1/platforms/linux64GccDPOpt/bin/RhaseChangeFoam"
NGinterPhaseChangeFoam"
[1] #4  [3] #6  __libc_start_main
[2]  in "/home/yusuke/OpenFOAM/yusuke-2.1.1/platforms/linux64GccDPOpt/bin/RNGinterPhaseChangeFoam"
[2] #5  
[6]  in "/home/yusuke/OpenFOAM/yusuke-2.1.1/platforms/linux64GccDPOpt/bin/RNGinterPhaseChangeFoam"
[6] #4  [10]  in "/home/yusuke/OpenFOAM/yusuke-2.1.1/platforms/linux64GccDPOpt/bin/RNGinterPhaseChangeFoam"
[10] #5   in "/lib/libc.so.6"
[11] #7  

[7]  in "/home/yusuke/OpenFOAM/yusuke-2.1.1/platforms/linux64GccDPOpt/bin/RNGinterPhaseChangeFoam"
[7] #6  __libc_start_main

 in "/lib/libc.so.6"
[3] #7  
[4]  in "/home/yusuke/OpenFOAM/yusuke-2.1.1/platforms/linux64GccDPOpt/bin/RNGinterPhaseChangeFoam"
[4] #5  [9]  in "/home/yusuke/OpenFOAM/yusuke-2.1.1/platforms/linux64GccDPOpt/bin/RNGinterPhaseChangeFoam"
[9] #6  __libc_start_main[6]  in "/home/yusuke/OpenFOAM/yusuke-2.1.1/platforms/linux64GccDPOpt/bin/RNGinterPhaseChangeFoam"
[6] #5   in "/lib/libc.so.6"
[7] #7  
[1]  in "/home/yusuke/OpenFOAM/yusuke-2.1.1/platforms/linux64GccDPOpt/bin/RNGinterPhaseChangeFoam"
[1] #5  [2]  in "/home/yusuke/OpenFOAM/yusuke-2.1.1/platforms/linux64GccDPOpt/bin/RNGinterPhaseChangeFoam"
[2] #6  __libc_start_main
[10]  in "/home/yusuke/OpenFOAM/yusuke-2.1.1/platforms/linux64GccDPOpt/bin/RNGinterPhaseChangeFoam"
[10] #6  __libc_start_main[5]  in "/home/yusuke/OpenFOAM/yusuke-2.1.1/platforms/linux64GccDPOpt/bin/RNGinterPhaseChangeFoam"
[5] #5  
[8]  in "/home/yusuke/OpenFOAM/yusuke-2.1.1/platforms/linux64GccDPOpt/bin/RNGinterPhaseChangeFoam"
[8] #4  
 in "/lib/libc.so.6"
[2] #7  

[11]  in "/home/yusuke/OpenFOAM/yusuke-2.1.1/platforms/linux64GccDPOpt/bin/RNGinterPhaseChangeFoam"
[VENUS:26554] *** Process received signal ***
[VENUS:26554] Signal: Floating point exception (8)
[VENUS:26554] Signal code:  (-6)
[VENUS:26554] Failing at address: 0x3e8000067ba
[VENUS:26554] [ 0] /lib/libc.so.6(+0x33af0) [0x7f17f47d3af0]
[VENUS:26554] [ 1] /lib/libc.so.6(gsignal+0x35) [0x7f17f47d3a75]
[VENUS:26554] [ 2] /lib/libc.so.6(+0x33af0) [0x7f17f47d3af0]
[VENUS:26554] [ 3] RNGinterPhaseChangeFoam() [0x4a8442]
[VENUS:26554] [ 4] RNGinterPhaseChangeFoam() [0x4b74fd]
[VENUS:26554] [ 5] RNGinterPhaseChangeFoam() [0x435358]
[VENUS:26554] [ 6] /lib/libc.so.6(__libc_start_main+0xfd) [0x7f17f47bec4d]
[VENUS:26554] [ 7] RNGinterPhaseChangeFoam() [0x42b849]
[VENUS:26554] *** End of error message ***
 in "/lib/libc.so.6"
[10] #7  [0]  in "/home/yusuke/OpenFOAM/yusuke-2.1.1/platforms/linux64GccDPOpt/bin/RNGinterPhaseChangeFoam"
[0] #5   in "/lib/libc.so.6"
[9] #7  [3]  in "/home/yusuke/OpenFOAM/yusuke-2.1.1/platforms/linux64GccDPOpt/bin/RNGinterPhaseChangeFoam"
[VENUS:26546] *** Process received signal ***
[VENUS:26546] Signal: Floating point exception (8)
[VENUS:26546] Signal code:  (-6)
[VENUS:26546] Failing at address: 0x3e8000067b2
[VENUS:26546] [ 0] /lib/libc.so.6(+0x33af0) [0x7ff896532af0]
[VENUS:26546] [ 1] /lib/libc.so.6(gsignal+0x35) [0x7ff896532a75]
[VENUS:26546] [ 2] /lib/libc.so.6(+0x33af0) [0x7ff896532af0]
[VENUS:26546] [ 3] RNGinterPhaseChangeFoam() [0x4a8483]
[VENUS:26546] [ 4] RNGinterPhaseChangeFoam() [0x4b74fd]
[VENUS:26546] [ 5] RNGinterPhaseChangeFoam() [0x435358]
[VENUS:26546] [ 6] /lib/libc.so.6(__libc_start_main+0xfd) [0x7ff89651dc4d]
[VENUS:26546] [ 7] RNGinterPhaseChangeFoam() [0x42b849]
[VENUS:26546] *** End of error message ***
[1]  in "/home/yusuke/OpenFOAM/yusuke-2.1.1/platforms/linux64GccDPOpt/bin/RNGinterPhaseChangeFoam"
[1] #6  __libc_start_main
And, finally when i viewed the result of P_rgh and U as you can see left side of the small throat entrance always obtained strange high velocity and very high inlet pressure.

I dont know what i can do .Please can someone guide and tell me some new ways..

Thanks in advance.

B
Attached Images
File Type: jpg P.jpg (51.6 KB, 16 views)
File Type: jpg U_vec.jpg (72.6 KB, 14 views)
File Type: jpg U_vec2.jpg (96.0 KB, 12 views)
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Old   March 22, 2014, 04:40
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  #2
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Bruno Santos
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Greetings Baris,

After a very quick read and looking at the images, my guess is that the problem is related to a bad mesh or due to insufficient resolution or big changes in resolution near the wall.

To understand what I mean, have a look into this blog post of mine: OpenFOAM: Interesting cases of bad meshes and bad initial conditions

Best regards,
Bruno
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Old   March 22, 2014, 05:26
Default hi
  #3
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Baris (Heewa)
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Dear Bruno,

Thanks so much for your reply.

About mesh, i checked it that seems OK as follows:

HTML Code:
Mesh stats
    points:           654382
    faces:            1596014
    internal faces:   1412748
    cells:            471322
    boundary patches: 3
    point zones:      0
    face zones:       0
    cell zones:       0

Overall number of cells of each type:
    hexahedra:     410213
    prisms:        0
    wedges:        0
    pyramids:      0
    tet wedges:    0
    tetrahedra:    0
    polyhedra:     61109

Checking topology...
    Boundary definition OK.
    Cell to face addressing OK.
    Point usage OK.
    Upper triangular ordering OK.
    Face vertices OK.
    Topological cell zip-up check OK.
    Face-face connectivity OK.
    Number of regions: 1 (OK).

Checking patch topology for multiply connected surfaces ...
    Patch               Faces    Points   Surface topology                   Bounding box
    wall                182766   183793   ok (non-closed singly connected)   (-0.006 -0.008 -2.71051e-20) (0.00194 0.007 0.00194)
    outlet              100      121      ok (non-closed singly connected)   (0 -0.008 0) (0.00194 -0.008 0.00194)
    inlet               400      451      ok (non-closed singly connected)   (-0.006 0.007 0) (0.00194 0.007 0.00194)

Checking geometry...
    Overall domain bounding box (-0.006 -0.008 -2.71051e-20) (0.00194 0.007 0.00194)
    Mesh (non-empty, non-wedge) directions (1 1 1)
    Mesh (non-empty) directions (1 1 1)
    Boundary openness (2.22526e-14 -1.42534e-17 -2.50737e-15) OK.
    Max cell openness = 2.06795e-16 OK.
    Max aspect ratio = 2.5 OK.
    Minumum face area = 3.75e-11. Maximum face area = 1.6e-07.  Face area magnitudes OK.
    Min volume = 7.03125e-16. Max volume = 6.4e-11.  Total volume = 1.37934e-07.  Cell volumes OK.
    Mesh non-orthogonality Max: 29.0546 average: 10.3431
    Non-orthogonality check OK.
    Face pyramids OK.
    Max skewness = 1.6129 OK.
    Coupled point location match (average 0) OK.
    Face tets OK.
    Min/max edge length = 5e-06 0.0004 OK.
    All angles in faces OK.
    Face flatness (1 = flat, 0 = butterfly) : average = 1  min = 1
    All face flatness OK.
    Cell determinant (wellposedness) : minimum: 0.821136 average: 13.565
    Cell determinant check OK.
About insufficient resolution or big changes in resolution near the wall, i will read your thread and let you know situation.

Thanks.

B.
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