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Diverging solution in transonicMRFDyMFoam

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Old   May 22, 2014, 04:42
Post Floating point exception (core dumped) in transonicMRFDyMFoam
  #21
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Hi ,
Here with I have attached BC and Constant files which gives the lower pressure ratio and revolution per second (RPS) as per your suggestion but i am finding Floating point exception (core dumped). The out put log file also attached. Please let me know if i have any discrepancies.
Please guide me . I am seriously in trouble as my thesis need to be submitted in July.
Need to validate my case with OpenFOAM results with experimental values.

how to give Mass flow rate input at Velocity file at INLET patch ?
Attached Files
File Type: zip BC.zip (12.6 KB, 9 views)
File Type: zip constant.zip (2.5 KB, 8 views)
File Type: zip log.zip (2.8 KB, 6 views)

Last edited by sam.ho; May 22, 2014 at 04:47. Reason: missed a question
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Old   May 23, 2014, 04:19
Post No convergence
  #22
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Hi,

I have changed some BC in velocity. As i knew flow rate for my case I gave as follows
Code:
    INLET 
    {
        type            flowRateInletVelocity;
        flowRate        0.0049454545;
        value           uniform (0 0 0);
    }
    OUTLET //11
    {
        type            zeroGradient;
    }
Pressure Conditions are as follows
Code:
 
   INLET
    {
        type            zeroGradient;
    }
    OUTLET
{
        type            fixedValue;
        value           uniform 105000.0;
    }
Temperature as follows
Code:
internalField   uniform 303;

boundaryField
{
    INLET //1
    {
        type      isentropicTotalTemperature;
        p         p;              // name of static pressure field
        T0        uniform 973.0;  // absolute total temperature field
        p0        uniform 125000; // absolute total presure field
        value     uniform 960.0;    // initial value atmospheric temperature is considered 
    } 
    OUTLET //11
    {
        type            zeroGradient;
    }
and log file is attached.
Mass convergence is not happening and temperature variation at inlet and outlet are high. Out let temperature expected to vary within 200 but in my case out velocity is remaining almost same "internalField uniform 303".
I gave inlet total temperature as 973 K. But why is it varying with iterations. Its an input given to case and should be constant Rite ?
please let me know how to get convergence.

Regards,
sam
Attached Files
File Type: zip log_1000to1500.zip (29.1 KB, 6 views)

Last edited by sam.ho; May 23, 2014 at 04:25. Reason: missed a question
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Old   May 27, 2014, 03:43
Default
  #23
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Quote:
Originally Posted by sam.ho View Post
Hi,

I have changed some BC in velocity. As i knew flow rate for my case I gave as follows
Code:
    INLET 
    {
        type            flowRateInletVelocity;
        flowRate        0.0049454545;
        value           uniform (0 0 0);
    }
    OUTLET //11
    {
        type            zeroGradient;
    }
Pressure Conditions are as follows
Code:
 
   INLET
    {
        type            zeroGradient;
    }
    OUTLET
{
        type            fixedValue;
        value           uniform 105000.0;
    }
Temperature as follows
Code:
internalField   uniform 303;

boundaryField
{
    INLET //1
    {
        type      isentropicTotalTemperature;
        p         p;              // name of static pressure field
        T0        uniform 973.0;  // absolute total temperature field
        p0        uniform 125000; // absolute total presure field
        value     uniform 960.0;    // initial value atmospheric temperature is considered 
    } 
    OUTLET //11
    {
        type            zeroGradient;
    }
and log file is attached.
Mass convergence is not happening and temperature variation at inlet and outlet are high. Out let temperature expected to vary within 200 but in my case out velocity is remaining almost same "internalField uniform 303".
I gave inlet total temperature as 973 K. But why is it varying with iterations. Its an input given to case and should be constant Rite ?
please let me know how to get convergence.

Regards,
sam
Hi sam, try in the following,
1) at inlet, specify total pressure, total temperature and direction of velocity direction
2)at outlet, specify static pressure, its value can be slightly lower than the total pressure at inlet;
3) set the rotation speed to zero,
4) in the file named "U", set the initial velocity vector in the domain and on the boundary to (0 0 0)
the above settings make the turbine like a nozzle. you can check it. In my cases, I usually do it like this.Good luck.
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Old   May 27, 2014, 04:52
Post
  #24
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Could you please explain me about rotational sign used in MRDzone file ?
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Old   May 28, 2014, 06:56
Post No convergence with transonicMRFDyMFOAM
  #25
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Hi,

I have simulated the case. Up to 1400 iterations everything went well. Ang got the results almost converged. Which is as follows
Code:
Time = 1400
MassFlows:   INLET = 0.050998309
 MassFlows:   OUTLET = 0.051097883
 Averages of p :  INLET = 122879.91  OUTLET = 105000
 Averages of rho :  INLET = 0.44092278  OUTLET = 0.42706291
 Averages of T :  INLET = 968.66311  OUTLET = 861.43023
 Averages of U :  INLET = (-93.909463 0 0)  OUTLET = (-1.7016498 2.2553501 142.98454)
After this I ran up to 1500 iterations and results suddenly started diverging. At the end mass flow is uncompilable with inlet.
The error message was
Code:
 From function specieThermo<thermo>::T(scalar f, scalar T0, scalar (specieThermo<thermo>::*F)(const scalar) const, scalar (specieThermo<thermo>::*dFdT)(const scalar) const) const
    in file /home/sml5kor/OpenFOAM/OpenFOAM-1.6-ext/src/thermophysicalModels/specie/lnInclude/specieThermoI.H at line 73
    Maximum number of iterations exceeded.  Rescue by HJ
What happened in your case ? Does results remain same after convergence or changed distinguishably ?
Can u share your case set up (only BC's MRFzone and system) ?

Regards,
Sangamesh Hosur
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Old   June 24, 2014, 03:12
Post transonicMRFDyMFoam
  #26
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HI Dowlee,

I have set up the case of radial inflow turbine passage and case is running absolutely fine.

But after convergence whyc there is a difference in mass flows at the inlet and outlet. which is shown below
Code:
MassFlows: INLET = 0.062517835
MassFlows: OUTLET = 0.054917385
Averages of p : INLET = 121854.22 OUTLET = 105000
Averages of rho : INLET = 0.43810996 OUTLET = 0.39981185
Averages of T : INLET = 966.74467 OUTLET = 912.84935
Averages of U : INLET = (-116.88216 0 0) OUTLET = (-2.1964329
-14.212135 160.62)
Even i have observed this in Axial_Rotor_MRF tutorial.

And also outlet temperature at the turbine outlet is too high as my TempFile is as below

Code:
/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM Extend Project: Open Source CFD        |
|  \\    /   O peration     | Version:  1.6-ext                               |
|   \\  /    A nd           | Web:      www.extend-project.de                 |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       volScalarField;
    location    "0";
    object      T;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions      [0 0 0 1 0 0 0];

internalField   uniform 900.0;

boundaryField
{
    INLET //1
    {
        type      isentropicTotalTemperature;
        p         p;              // name of static pressure field
        T0        uniform 973.0;  // absolute total temperature field
        p0        uniform 125000; // absolute total presure field
        value     uniform 900.0;    // initial value atmospheric temperature is considered 
    }   
    SHR_UPS //2
    {
        type            zeroGradient;
    }
    HUB_UPS //3
    {
        type            zeroGradient;
    }
    IFC1_UPS_TO_IMP //4
    {
        type            overlapGgi;
    }
    RAD_HUB //5
    {
        type            zeroGradient;
    }
    RAD_SHR //6
    {
        type            zeroGradient;
    }
    RAD_BLADE_0 //7 
    {
        type            zeroGradient;
    }
    BLADE_TIP //8
    {
        type            zeroGradient;
    }
    IFC2_UPS_TO_IMP //9 
    {
        type            overlapGgi;
    }
    IFC1_IMP_TO_UPS //10
    {
        type            overlapGgi;
    }
    OUTLET //11
    {
        type            zeroGradient;
    }
    HUB_DWS //12 
    {
        type            zeroGradient;
    }
    SHROUD_DWS //13 
    {
        type            zeroGradient;
    }
    IFC2_IMP_TO_DWS //14
    {
        type            overlapGgi;
    }
    PERIODIC1 //15
    {
        type         cyclicGgi;
    }

    PERIODIC2 //16
    {
        type         cyclicGgi;
    }
    PER1_DWS //17
    {
        type         cyclicGgi;
    }
    PER2_DWS //18
    {
        type         cyclicGgi;
    }
    PER1_UPS //19
    {
        type         cyclicGgi;
    }
    PER2_UPS //20
    {
        type         cyclicGgi;
    }

      
}

// ************************************************************************* //
Can you tell me whats the reason for these ?
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Old   June 24, 2014, 04:09
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Quote:
Originally Posted by sam.ho View Post
HI Dowlee,

I have set up the case of radial inflow turbine passage and case is running absolutely fine.

But after convergence whyc there is a difference in mass flows at the inlet and outlet. which is shown below
Code:
MassFlows: INLET = 0.062517835
MassFlows: OUTLET = 0.054917385
Averages of p : INLET = 121854.22 OUTLET = 105000
Averages of rho : INLET = 0.43810996 OUTLET = 0.39981185
Averages of T : INLET = 966.74467 OUTLET = 912.84935
Averages of U : INLET = (-116.88216 0 0) OUTLET = (-2.1964329
-14.212135 160.62)
Even i have observed this in Axial_Rotor_MRF tutorial.

And also outlet temperature at the turbine outlet is too high as my TempFile is as below

Code:
/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM Extend Project: Open Source CFD        |
|  \\    /   O peration     | Version:  1.6-ext                               |
|   \\  /    A nd           | Web:      www.extend-project.de                 |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       volScalarField;
    location    "0";
    object      T;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions      [0 0 0 1 0 0 0];

internalField   uniform 900.0;

boundaryField
{
    INLET //1
    {
        type      isentropicTotalTemperature;
        p         p;              // name of static pressure field
        T0        uniform 973.0;  // absolute total temperature field
        p0        uniform 125000; // absolute total presure field
        value     uniform 900.0;    // initial value atmospheric temperature is considered 
    }   
    SHR_UPS //2
    {
        type            zeroGradient;
    }
    HUB_UPS //3
    {
        type            zeroGradient;
    }
    IFC1_UPS_TO_IMP //4
    {
        type            overlapGgi;
    }
    RAD_HUB //5
    {
        type            zeroGradient;
    }
    RAD_SHR //6
    {
        type            zeroGradient;
    }
    RAD_BLADE_0 //7 
    {
        type            zeroGradient;
    }
    BLADE_TIP //8
    {
        type            zeroGradient;
    }
    IFC2_UPS_TO_IMP //9 
    {
        type            overlapGgi;
    }
    IFC1_IMP_TO_UPS //10
    {
        type            overlapGgi;
    }
    OUTLET //11
    {
        type            zeroGradient;
    }
    HUB_DWS //12 
    {
        type            zeroGradient;
    }
    SHROUD_DWS //13 
    {
        type            zeroGradient;
    }
    IFC2_IMP_TO_DWS //14
    {
        type            overlapGgi;
    }
    PERIODIC1 //15
    {
        type         cyclicGgi;
    }

    PERIODIC2 //16
    {
        type         cyclicGgi;
    }
    PER1_DWS //17
    {
        type         cyclicGgi;
    }
    PER2_DWS //18
    {
        type         cyclicGgi;
    }
    PER1_UPS //19
    {
        type         cyclicGgi;
    }
    PER2_UPS //20
    {
        type         cyclicGgi;
    }

      
}

// ************************************************************************* //
Can you tell me whats the reason for these ?

Hi I think mostly this is related to the mesh. implement the following command and have a look at the mesh quality,
checkMesh -allTopology -allGeometry -constant

now the newest version for openfoam extend project is foam-extend-3.1. And inside it there is a sovler named steadyCompressibleMRFFoam which can be used for turbomachinery. You can have a try by using this newly release solver.
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Old   June 24, 2014, 04:22
Post
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Output of the command

Code:
sml5kor@BMH301562:~/OpenFOAM/sml5kor-1.6-ext/run/TURBINE_cyclicGGI_2/finel_merge_2/Case_with_initial_volcity_field_high_k-omega$ checkMesh -allTopology -allGeometry -constant
/*---------------------------------------------------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM Extend Project: Open source CFD        |
|  \\    /   O peration     | Version:  1.6-ext                               |
|   \\  /    A nd           | Web:      www.extend-project.de                 |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
Build  : 1.6-ext
Exec   : checkMesh -allTopology -allGeometry -constant
Date   : Jun 24 2014
Time   : 13:50:10
Host   : BMH301562
PID    : 32477
Case   : /home/sml5kor/OpenFOAM/sml5kor-1.6-ext/run/TURBINE_cyclicGGI_2/finel_merge_2/Case_with_initial_volcity_field_high_k-omega
nProcs : 1
SigFpe : Enabling floating point exception trapping (FOAM_SIGFPE).

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
Create time

Create polyMesh for time = constant

Initializing the GGI interpolator between master/shadow patches: PER1_UPS/PER2_UPS
Initializing the GGI interpolator between master/shadow patches: PERIODIC1/PERIODIC2
Initializing the GGI interpolator between master/shadow patches: PER1_DWS/PER2_DWS
Time = constant

Mesh stats
    all points:           652866
    live points:           652866
    all faces:            1885491
    live faces:            1885491
    internal faces:   1813845
    cells:            616556
    boundary patches: 20
    point zones:      0
    face zones:       13
    cell zones:       6

Overall number of cells of each type:
    hexahedra:     616556
    prisms:        0
    wedges:        0
    pyramids:      0
    tet wedges:    0
    tetrahedra:    0
    polyhedra:     0

Checking topology...
    Boundary definition OK.
    Point usage OK.
    Upper triangular ordering OK.
    Topological cell zip-up check OK.
    Face vertices OK.
    Face-face connectivity OK.
   *Number of regions: 3
    The mesh has multiple regions which are not connected by any face.
  <<Writing region information to "constant/cellToRegion"

Checking patch topology for multiply connected surfaces ...
    Patch               Faces    Points   Surface topology                   Bounding box
    INLET               4402     4536     ok (non-closed singly connected)   (0.028963776 -0.0085061541 4.3901804e-19) (0.030186862 0.0085049543 0.00652312)
    SHR_UPS             1491     1584     ok (non-closed singly connected)   (0.023331164 -0.0085043668 0.0065231199) (0.030186087 0.0085049543 0.00652312)
    HUB_UPS             1491     1584     ok (non-closed singly connected)   (0.023330961 -0.0085058132 4.3901804e-19) (0.030186099 0.0085035082 4.3901805e-19)
    PER1_UPS            1302     1386     ok (non-closed singly connected)   (0.023330961 -0.0085061541 4.3901804e-19) (0.0289643 -0.0068504314 0.00652312)
    PER2_UPS            1302     1386     ok (non-closed singly connected)   (0.023331164 0.0068497398 4.3901804e-19) (0.028964653 0.0085049543 0.00652312)
    IFC1_UPS_TO_IMP     4402     4536     ok (non-closed singly connected)   (0.023330961 -0.0068515966 4.3901804e-19) (0.024316069 0.0068509049 0.00652312)
    PERIODIC1           4216     4347     ok (non-closed singly connected)   (0.0051635397 -0.0095592735 4.3901804e-19) (0.023331303 -0.0027305049 0.01864559)
    PERIODIC2           4216     4347     ok (non-closed singly connected)   (0.0061525676 -0.00010298083 4.3901804e-19) (0.0233315 0.0068509049 0.01864559)
    RAD_HUB             3586     3802     ok (non-closed singly connected)   (0.0051635397 -0.0068516134 -9.865518e-12) (0.024315742 0.0068497157 0.018663031)
    RAD_SHR             7446     7586     ok (non-closed singly connected)   (0.014784628 -0.0095592735 0.0065231199) (0.024309277 0.0068509049 0.01864559)
    RAD_BLADE_0         6006     6160     ok (non-closed singly connected)   (0.005537279 -0.0055899046 -9.865518e-12) (0.023663878 0.0011922848 0.017550802)
    BLADE_TIP           2474     2552     ok (non-closed singly connected)   (0.016455274 -0.0055899046 0.0064015365) (0.023662441 0.0002629348 0.017535285)
    IFC2_UPS_TO_IMP     4402     4536     ok (non-closed singly connected)   (0.023330942 -0.0068516134 4.3901804e-19) (0.024315742 0.0068509049 0.0065231199)
    IFC1_IMP_TO_UPS     4402     4536     ok (non-closed singly connected)   (0.0051635397 -0.0095592735 0.018643549) (0.017605754 -2.2805322e-05 0.018663031)
    OUTLET              4402     4536     ok (non-closed singly connected)   (0.0051635013 -0.0095609661 0.0489646) (0.017605827 -2.2876245e-05 0.0489646)
    PER1_DWS            2728     2835     ok (non-closed singly connected)   (0.0051629153 -0.0095661627 0.018645527) (0.014784688 -0.0033455142 0.0489646)
    PER2_DWS            2728     2835     ok (non-closed singly connected)   (0.0061525657 -0.00010649717 0.018645527) (0.017605839 6.4763128e-06 0.0489646)
    HUB_DWS             3124     3240     ok (non-closed singly connected)   (0.0051629153 -0.0033464822 0.018645577) (0.0061525676 -2.2805327e-05 0.0489646)
    SHROUD_DWS          3124     3240     ok (non-closed singly connected)   (0.014780302 -0.0095661627 0.018645525) (0.017605839 -4.8596013e-05 0.0489646)
    IFC2_IMP_TO_DWS     4402     4536     ok (non-closed singly connected)   (0.0051635397 -0.0095593084 0.018645525) (0.017605824 6.4763128e-06 0.018663211)

Checking geometry...
    This is a 3-D mesh
    Overall domain bounding box (0.0051629153 -0.0095661627 -9.865518e-12) (0.030186862 0.0085049543 0.0489646)
    Mesh (non-empty, non-wedge) directions (1 1 1)
    Mesh (non-empty) directions (1 1 1)
    Mesh (non-empty, non-wedge) dimensions 3
    Boundary openness (-6.3795052e-16 1.6164244e-16 -3.1703713e-16) Threshold = 1e-06 OK.
    Max cell openness = 4.7481174e-15 OK.
    Max aspect ratio = 248.69674 OK.
    Minumum face area = 5.5833299e-12. Maximum face area = 1.0159705e-06.  Face area magnitudes OK.
    Min volume = 3.7092636e-17. Max volume = 2.1934866e-10.  Total volume = 4.3995348e-06.  Cell volumes OK.
    Mesh non-orthogonality Max: 86.541631 average: 18.373099 Threshold = 70
   *Number of severely non-orthogonal faces: 1261.
    Non-orthogonality check OK.
  Writing 1261 non-orthogonal faces to set nonOrthoFaces
    Face pyramids OK.
 ***Max skewness = 4.3764234, 4 highly skew faces detected Threshold = 4
  Writing 4 skew faces to set skewFaces
    Min/max edge length = 1.1174641e-06 0.0011549148 OK.
  Writing 192 near (closer than 5.7881735e-08 apart) points to set nearPoints
    All angles in faces OK.
    Face flatness (1 = flat, 0 = butterfly) : average = 0.99997935  min = 0.9442212
    All face flatness OK.
    Cell determinant (wellposedness) : minimum: 2.3853008e-09 average: 0.98973614
 ***Cells with small determinant found, number of cells: 19269
  Writing 19269 under-determined cells to set underdeterminedCells

Failed 2 mesh checks.

End
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Old   June 24, 2014, 06:40
Default
  #29
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Quote:
Originally Posted by sam.ho View Post
Output of the command

Code:
sml5kor@BMH301562:~/OpenFOAM/sml5kor-1.6-ext/run/TURBINE_cyclicGGI_2/finel_merge_2/Case_with_initial_volcity_field_high_k-omega$ checkMesh -allTopology -allGeometry -constant
/*---------------------------------------------------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM Extend Project: Open source CFD        |
|  \\    /   O peration     | Version:  1.6-ext                               |
|   \\  /    A nd           | Web:      www.extend-project.de                 |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
Build  : 1.6-ext
Exec   : checkMesh -allTopology -allGeometry -constant
Date   : Jun 24 2014
Time   : 13:50:10
Host   : BMH301562
PID    : 32477
Case   : /home/sml5kor/OpenFOAM/sml5kor-1.6-ext/run/TURBINE_cyclicGGI_2/finel_merge_2/Case_with_initial_volcity_field_high_k-omega
nProcs : 1
SigFpe : Enabling floating point exception trapping (FOAM_SIGFPE).

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
Create time

Create polyMesh for time = constant

Initializing the GGI interpolator between master/shadow patches: PER1_UPS/PER2_UPS
Initializing the GGI interpolator between master/shadow patches: PERIODIC1/PERIODIC2
Initializing the GGI interpolator between master/shadow patches: PER1_DWS/PER2_DWS
Time = constant

Mesh stats
    all points:           652866
    live points:           652866
    all faces:            1885491
    live faces:            1885491
    internal faces:   1813845
    cells:            616556
    boundary patches: 20
    point zones:      0
    face zones:       13
    cell zones:       6

Overall number of cells of each type:
    hexahedra:     616556
    prisms:        0
    wedges:        0
    pyramids:      0
    tet wedges:    0
    tetrahedra:    0
    polyhedra:     0

Checking topology...
    Boundary definition OK.
    Point usage OK.
    Upper triangular ordering OK.
    Topological cell zip-up check OK.
    Face vertices OK.
    Face-face connectivity OK.
   *Number of regions: 3
    The mesh has multiple regions which are not connected by any face.
  <<Writing region information to "constant/cellToRegion"

Checking patch topology for multiply connected surfaces ...
    Patch               Faces    Points   Surface topology                   Bounding box
    INLET               4402     4536     ok (non-closed singly connected)   (0.028963776 -0.0085061541 4.3901804e-19) (0.030186862 0.0085049543 0.00652312)
    SHR_UPS             1491     1584     ok (non-closed singly connected)   (0.023331164 -0.0085043668 0.0065231199) (0.030186087 0.0085049543 0.00652312)
    HUB_UPS             1491     1584     ok (non-closed singly connected)   (0.023330961 -0.0085058132 4.3901804e-19) (0.030186099 0.0085035082 4.3901805e-19)
    PER1_UPS            1302     1386     ok (non-closed singly connected)   (0.023330961 -0.0085061541 4.3901804e-19) (0.0289643 -0.0068504314 0.00652312)
    PER2_UPS            1302     1386     ok (non-closed singly connected)   (0.023331164 0.0068497398 4.3901804e-19) (0.028964653 0.0085049543 0.00652312)
    IFC1_UPS_TO_IMP     4402     4536     ok (non-closed singly connected)   (0.023330961 -0.0068515966 4.3901804e-19) (0.024316069 0.0068509049 0.00652312)
    PERIODIC1           4216     4347     ok (non-closed singly connected)   (0.0051635397 -0.0095592735 4.3901804e-19) (0.023331303 -0.0027305049 0.01864559)
    PERIODIC2           4216     4347     ok (non-closed singly connected)   (0.0061525676 -0.00010298083 4.3901804e-19) (0.0233315 0.0068509049 0.01864559)
    RAD_HUB             3586     3802     ok (non-closed singly connected)   (0.0051635397 -0.0068516134 -9.865518e-12) (0.024315742 0.0068497157 0.018663031)
    RAD_SHR             7446     7586     ok (non-closed singly connected)   (0.014784628 -0.0095592735 0.0065231199) (0.024309277 0.0068509049 0.01864559)
    RAD_BLADE_0         6006     6160     ok (non-closed singly connected)   (0.005537279 -0.0055899046 -9.865518e-12) (0.023663878 0.0011922848 0.017550802)
    BLADE_TIP           2474     2552     ok (non-closed singly connected)   (0.016455274 -0.0055899046 0.0064015365) (0.023662441 0.0002629348 0.017535285)
    IFC2_UPS_TO_IMP     4402     4536     ok (non-closed singly connected)   (0.023330942 -0.0068516134 4.3901804e-19) (0.024315742 0.0068509049 0.0065231199)
    IFC1_IMP_TO_UPS     4402     4536     ok (non-closed singly connected)   (0.0051635397 -0.0095592735 0.018643549) (0.017605754 -2.2805322e-05 0.018663031)
    OUTLET              4402     4536     ok (non-closed singly connected)   (0.0051635013 -0.0095609661 0.0489646) (0.017605827 -2.2876245e-05 0.0489646)
    PER1_DWS            2728     2835     ok (non-closed singly connected)   (0.0051629153 -0.0095661627 0.018645527) (0.014784688 -0.0033455142 0.0489646)
    PER2_DWS            2728     2835     ok (non-closed singly connected)   (0.0061525657 -0.00010649717 0.018645527) (0.017605839 6.4763128e-06 0.0489646)
    HUB_DWS             3124     3240     ok (non-closed singly connected)   (0.0051629153 -0.0033464822 0.018645577) (0.0061525676 -2.2805327e-05 0.0489646)
    SHROUD_DWS          3124     3240     ok (non-closed singly connected)   (0.014780302 -0.0095661627 0.018645525) (0.017605839 -4.8596013e-05 0.0489646)
    IFC2_IMP_TO_DWS     4402     4536     ok (non-closed singly connected)   (0.0051635397 -0.0095593084 0.018645525) (0.017605824 6.4763128e-06 0.018663211)

Checking geometry...
    This is a 3-D mesh
    Overall domain bounding box (0.0051629153 -0.0095661627 -9.865518e-12) (0.030186862 0.0085049543 0.0489646)
    Mesh (non-empty, non-wedge) directions (1 1 1)
    Mesh (non-empty) directions (1 1 1)
    Mesh (non-empty, non-wedge) dimensions 3
    Boundary openness (-6.3795052e-16 1.6164244e-16 -3.1703713e-16) Threshold = 1e-06 OK.
    Max cell openness = 4.7481174e-15 OK.
    Max aspect ratio = 248.69674 OK.
    Minumum face area = 5.5833299e-12. Maximum face area = 1.0159705e-06.  Face area magnitudes OK.
    Min volume = 3.7092636e-17. Max volume = 2.1934866e-10.  Total volume = 4.3995348e-06.  Cell volumes OK.
    Mesh non-orthogonality Max: 86.541631 average: 18.373099 Threshold = 70
   *Number of severely non-orthogonal faces: 1261.
    Non-orthogonality check OK.
  Writing 1261 non-orthogonal faces to set nonOrthoFaces
    Face pyramids OK.
 ***Max skewness = 4.3764234, 4 highly skew faces detected Threshold = 4
  Writing 4 skew faces to set skewFaces
    Min/max edge length = 1.1174641e-06 0.0011549148 OK.
  Writing 192 near (closer than 5.7881735e-08 apart) points to set nearPoints
    All angles in faces OK.
    Face flatness (1 = flat, 0 = butterfly) : average = 0.99997935  min = 0.9442212
    All face flatness OK.
    Cell determinant (wellposedness) : minimum: 2.3853008e-09 average: 0.98973614
 ***Cells with small determinant found, number of cells: 19269
  Writing 19269 under-determined cells to set underdeterminedCells

Failed 2 mesh checks.

End
As I know, OpenFOAM is very sensitive to the mesh quality. You should make checkMesh happy. In your case, it complains two problems, especially the under-determined cells may effect the convergence of your calculation.
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Old   June 26, 2014, 02:47
Post Turbo Performance Problem
  #30
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Join Date: Sep 2013
Location: Bangalore India
Posts: 134
Rep Power: 4
sam.ho is on a distinguished road
Hi,

I have improved the quality of mesh and checked the mesh quality before simulation. It gave Mesh OK message. Now simulation is going on.
But i have attached turbo performance code in controlDict as follows.

Code:
turboPerformance
   {
       type turboPerformance;
       functionObjectLibs ("libturboPerformance.so");
       turbine true;                        // Turbine mode, (false if Pump)
//
       log true;                                // write data to screen (true/false)
       outputControl timeStep;    // write data to file (same options as case output)
       outputInterval 10;                 // interval to write data to file
//
       inletPatches (INLET);           // inlet patches, can be multiple
       outletPatches (OUTLET);      // outlet patches, can be multiple
       patches (RAD_BLADE_0 RAD_HUB RAD_SHR BLADE_TIP PERIODIC1 PERIODIC2 IFC1_IMP_TO_UPS IFC2_UPS_TO_IMP); // rotor/impeller patches, again can be multiple
//
       rhoInf 0.3547;                      // density
       CofR (0 0 0);                      // center of rotation
       omega (0 0 1179.3833333333);      // Rotational velocity (rad/s)
    /*
       pName  p;               //Optional: if p field is not called "p", give a new name here
       Uname Uabs;         //Optional: if U field is not called "U", give a new name here
       phiName phi;         //Optional: if phi (flux) field is not called "phi", give a new name here
    */
   }
   fluidPower
   {
       type fluidPower;
       functionObjectLibs ("libturboPerformance.so");
//
       turbine true;             // Turbine mode, (false if Pump)
//
       log true;                  // write data to screen (true/false)
       outputControl timeStep;    // write data to file (same options as case output)
       outputInterval 10;          // interval to write data to file
//
       inletPatches (INLET);
       outletPatches (OUTLET);
       rhoInf 0.3547;
   }
Ref : http://openfoamwiki.net/index.php/Si...rboPerformance

But the values obtained are very strange which are as follows

Code:
 performance data:
   Head (m)   = -1982.5526
   TOmega (W) = 4.3479324
   Eff (%)    = -5.3890478
   Forces     = (-0.36608541 0.42663492 -0.39401571)
   Moments    = (-0.0051551442 0.0042789996 0.0036866151)

 Fluid power output:
  dEm (W) = -80.680903
  Head (m) = -1982.5526
Why is it so ?
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Old   July 7, 2014, 06:20
Post Need a paper
  #31
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Join Date: Sep 2013
Location: Bangalore India
Posts: 134
Rep Power: 4
sam.ho is on a distinguished road
Hi,
Anybody is having this paper ?
Code:
O. Borm et al., Density based navier stokes solver for transonic 
ows," OpenFoam 6th workshop, 2011.
I am in need this the paper . Please share with me .
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