[goswami]

Originally Posted by hjasak

Starting a post with an insult isn’t good. Foam-extend is not buggy and I put a lot of effort into doing things right. Perhaps the problem is somewhere else.

For a periodic channel, use pressure jump boundary conditions: this is a much more stable way of dealing with the flow. You change one boundary condition in one file.

Regarding validation and Re numbers, kindly read - and quote - the papers! We make sure the cases used in papers are publicly available and all results are reporoducable.

Hrvoje Jasak

I apologize if it seems like an insult Dr. Jasak, but personally my experience with foam-extend isn't really good. But that's not what I want to discuss here.

Regarding the validation, I agree, the tutorial cases in viscoelasticFluidFoam solver are well validated. But the problem is they're at a very low Reynolds number. The same concern is posted in another post here by someone else, that there is a lack of literature at high Reynolds numbers using this solver.

Thank you for the periodic pressure jump boundary condition. I should try that.

[Grace1]

Hello everyone,


May you kindly assist me, I have modified the viscoelastic solver by adding a temperature equation.

fvm::ddt((rho*Cp),T)
+ fvm::div((rho*Cp*phi),T)
- fvm::laplacian(k,T) ==
gamma*(visco.tau() && fvc::grad(U))
+ (1.0-gamma)*(1.0-beta)*(symm(fvc::grad(U)) && symm(fvc::grad(U)))
- fvm::Sp(hc,Tw)+hc*T
);
where Tw is wall temperature and T fluid temperature


and these are the dimensions of the coefficients used


rho rho [1 -3 0 0 0 0 0]

gamma gamma [0 0 0 0 0 0 0]

beta beta [0 0 0 0 0 0 0]

k k [1 1 -3 -1 0 0 0]

Cp Cp [0 2 -2 -1 0 0 0]

hc hc [1 0 -3 -1 0 0 0]



when I run the case file I keep getting this error


--> FOAM FATAL ERROR:
LHS and RHS of + have different dimensions
dimensions : [1 -1 -3 0 0 0 0] + [0 0 -2 0 0 0 0]


From function operator+(const dimensionSet& ds1, const dimensionSet& ds2)
in file dimensionSet/dimensionSet.C at line 407.


Not sure how to resolve this issue or where the dimension problem is coming from, may you kindly assist me


thanks

[alimea]

Originally Posted by Grace1

Hello everyone,


May you kindly assist me, I have modified the viscoelastic solver by adding a temperature equation.

fvm::ddt((rho*Cp),T)
+ fvm::div((rho*Cp*phi),T)
- fvm::laplacian(k,T) ==
gamma*(visco.tau() && fvc::grad(U))
+ (1.0-gamma)*(1.0-beta)*(symm(fvc::grad(U)) && symm(fvc::grad(U)))
- fvm::Sp(hc,Tw)+hc*T
);
where Tw is wall temperature and T fluid temperature


and these are the dimensions of the coefficients used


rho rho [1 -3 0 0 0 0 0]

gamma gamma [0 0 0 0 0 0 0]

beta beta [0 0 0 0 0 0 0]

k k [1 1 -3 -1 0 0 0]

Cp Cp [0 2 -2 -1 0 0 0]

hc hc [1 0 -3 -1 0 0 0]



when I run the case file I keep getting this error


--> FOAM FATAL ERROR:
LHS and RHS of + have different dimensions
dimensions : [1 -1 -3 0 0 0 0] + [0 0 -2 0 0 0 0]


From function operator+(const dimensionSet& ds1, const dimensionSet& ds2)
in file dimensionSet/dimensionSet.C at line 407.


Not sure how to resolve this issue or where the dimension problem is coming from, may you kindly assist me


thanks

Dear Asanda

As you can see in the error the dimensions of the two terms are different in the energy eqn. I saw that all your first term dimension is [1 -1 -3 0 0 0 0], the same as the other erms. But the dimension of (1.0-gamma)*(1.0-beta)*(symm(fvc::grad(U)) && symm(fvc::grad(U))) is [0 0 -2 0 0 0 0]. You should check the reference from that you found the equation. There are some other dimensioned parameters before (symm(fvc::grad(U)) && symm(fvc::grad(U))) that you might forget to consider.

Regards,
Ali

[Grace1]

Dear Ali

Firstly thank you for your response,

Thank you, with your assistance and guidance I was able to resolve my problem. And yes indeed there was a dimensioned parameter - the polymeric viscosity- which I needed to multiply with this term (symm(fvc::grad(U)) && symm(fvc::grad(U))).

[Grace1]

Hello Everyone

May you kindly assist me,

I am using viscoelasticFluidFoam solver and the Giesekus Model to simulate a flow in a pipe. And have modified both by adding temperature.

Now every time I run my simulation it gives me the below error and have tried to reduce delta T, Max Co. number and even check velocity value but nothing seems to be working

Courant Number mean: 8.19815e-06 max: 0.0016354 velocity magnitude: 0.336024
deltaT = 0.000121669
Time = 0.000730166

DILUPBiCG: Solving for Ux, Initial residual = 0.00475588, Final residual = 9.01518e-08, No Iterations 1
DILUPBiCG: Solving for Uy, Initial residual = 0.00477491, Final residual = 5.60245e-09, No Iterations 1
DILUPBiCG: Solving for Uz, Initial residual = 0.00153646, Final residual = 3.99944e-09, No Iterations 1
DICPCG: Solving for p, Initial residual = 0.202343, Final residual = 9.65702e-08, No Iterations 322
time step continuity errors : sum local = 1.74596e-13, global = -1.10905e-14, cumulative = -1.43122e-14
Model mode 1
DILUPBiCG: Solving for taufirstxx, Initial residual = 0.00504237, Final residual = 2.64016e-15, No Iterations 1
DILUPBiCG: Solving for taufirstxy, Initial residual = 0.00719778, Final residual = 1.69566e-15, No Iterations 1
DILUPBiCG: Solving for taufirstxz, Initial residual = 0.00372445, Final residual = 1.81474e-17, No Iterations 1
DILUPBiCG: Solving for taufirstyy, Initial residual = 0.00513511, Final residual = 2.97488e-15, No Iterations 1
DILUPBiCG: Solving for taufirstyz, Initial residual = 0.00372444, Final residual = 2.90091e-18, No Iterations 1
DILUPBiCG: Solving for taufirstzz, Initial residual = 0.00360069, Final residual = 9.85626e-17, No Iterations 1
Model mode 2
DILUPBiCG: Solving for tausecondxx, Initial residual = 0.00901374, Final residual = 4.5788e-16, No Iterations 1
DILUPBiCG: Solving for tausecondxy, Initial residual = 0.011415, Final residual = 3.71279e-16, No Iterations 1
DILUPBiCG: Solving for tausecondxz, Initial residual = 0.00373582, Final residual = 1.74955e-17, No Iterations 1
DILUPBiCG: Solving for tausecondyy, Initial residual = 0.00924354, Final residual = 6.99518e-16, No Iterations 1
DILUPBiCG: Solving for tausecondyz, Initial residual = 0.00373581, Final residual = 1.75101e-17, No Iterations 1
DILUPBiCG: Solving for tausecondzz, Initial residual = 0.00294321, Final residual = 5.88967e-17, No Iterations 1
Model mode 3
DILUPBiCG: Solving for tauthirdxx, Initial residual = 0.00929762, Final residual = 1.30313e-16, No Iterations 1
DILUPBiCG: Solving for tauthirdxy, Initial residual = 0.0117061, Final residual = 4.89053e-17, No Iterations 1
DILUPBiCG: Solving for tauthirdxz, Initial residual = 0.00373792, Final residual = 1.78278e-17, No Iterations 1
DILUPBiCG: Solving for tauthirdyy, Initial residual = 0.00953793, Final residual = 1.59044e-16, No Iterations 1
DILUPBiCG: Solving for tauthirdyz, Initial residual = 0.00373792, Final residual = 1.9548e-17, No Iterations 1
DILUPBiCG: Solving for tauthirdzz, Initial residual = 0.0026507, Final residual = 5.17534e-18, No Iterations 1
Model mode 4
DILUPBiCG: Solving for taufourthxx, Initial residual = 0.00940334, Final residual = 3.38134e-17, No Iterations 1
DILUPBiCG: Solving for taufourthxy, Initial residual = 0.0118159, Final residual = 1.53916e-17, No Iterations 1
DILUPBiCG: Solving for taufourthxz, Initial residual = 0.00373861, Final residual = 7.48391e-18, No Iterations 1
DILUPBiCG: Solving for taufourthyy, Initial residual = 0.00964937, Final residual = 8.37758e-17, No Iterations 1
DILUPBiCG: Solving for taufourthyz, Initial residual = 0.00373861, Final residual = 1.28578e-17, No Iterations 1
DILUPBiCG: Solving for taufourthzz, Initial residual = 0.00246207, Final residual = 8.77819e-17, No Iterations 1
DILUPBiCG: Solving for T, Initial residual = 0.45522, Final residual = 7.40274e-09, No Iterations 5
DILUPBiCG: Solving for Tw, Initial residual = 0.0828233, Final residual = 1.66062e-08, No Iterations 4
Floating point exception (core dumped)

CHECKMESH :

Create time

Create polyMesh for time = 0

Time = 0

Mesh stats
all points: 222101
live points: 222101
all faces: 654000
live faces: 654000
internal faces: 642000
cells: 216000
boundary patches: 3
point zones: 0
face zones: 0
cell zones: 0

Overall number of cells of each type:
hexahedra: 216000
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.
Face vertices OK.
Number of regions: 1 (OK).

Checking patch topology for multiply connected surfaces ...
Patch Faces Points Area [m^2] Surface topology
inlet 3600 3641 0.00196148 ok (non-closed singly connected)
outlet 3600 3641 0.00196148 ok (non-closed singly connected)
pipewall 4800 4880 0.392598 ok (non-closed singly connected)

Checking geometry...
This is a 3-D mesh
Overall domain bounding box (-0.025 -0.025 0) (0.025 0.025 2.5)
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 (2.02337e-16 2.16504e-16 4.25812e-17) Threshold = 1e-06 OK.
Max cell openness = 2.74096e-16 OK.
Max aspect ratio = 195.315 OK.
Minumum face area = 3.67922e-07. Maximum face area = 8.17913e-05. Face area magnitudes OK.
Min volume = 1.53301e-08. Max volume = 2.95413e-08. Total volume = 0.00490369. Cell volumes OK.
Mesh non-orthogonality Max: 37.1451 average: 5.71625 Threshold = 70
Non-orthogonality check OK.
Face pyramids OK.
Max skewness = 0.569773 OK.

Mesh OK.

CONTROL DICT:
startFrom startTime;

startTime 0.0;

stopAt endTime;

endTime 2;

deltaT 1e-16;

writeControl adjustableRunTime;

writeInterval 1;

purgeWrite 0;

writeFormat ascii;

writePrecision 6;

writeCompression uncompressed;

timeFormat general;

timePrecision 6;

graphFormat raw;

runTimeModifiable yes;

adjustTimeStep on;

maxCo 0.25;

maxDeltaT 0.001;


I am not sure on how else to resolve this issue . May you kindly assist me or provide some guidance on how to resolve this problem


Thanks in advance

[sita]

Hi Grace,

Without having seen your geometry, mesh, boundary conditions, etc. I can't say much I'm afraid. However, from working with viscoelasticFluidFoam myself (ages ago...) I remember that the mesh close to walls should be extremely fine. Did you try your adapted Giesekus model on the tutorial geometry included by Jovani Favero?

Sita

EDIT: Oh, and also I remember using very small (adaptive) time steps, something on the order of 1e-5. But again, without having seen your case, I'm not sure whether that'll help you

P.S. Tip: when including OpenFOAM code or output, you can wrap it in [CODE] tags, using the #-button in your toolbar, so that it won't take up as much space. Like so:

Courant Number mean: 8.19815e-06 max: 0.0016354 velocity magnitude: 0.336024
deltaT = 0.000121669
Time = 0.000730166

DILUPBiCG: Solving for Ux, Initial residual = 0.00475588, Final residual = 9.01518e-08, No Iterations 1
DILUPBiCG: Solving for Uy, Initial residual = 0.00477491, Final residual = 5.60245e-09, No Iterations 1
DILUPBiCG: Solving for Uz, Initial residual = 0.00153646, Final residual = 3.99944e-09, No Iterations 1
DICPCG: Solving for p, Initial residual = 0.202343, Final residual = 9.65702e-08, No Iterations 322
time step continuity errors : sum local = 1.74596e-13, global = -1.10905e-14, cumulative = -1.43122e-14
Model mode 1
DILUPBiCG: Solving for taufirstxx, Initial residual = 0.00504237, Final residual = 2.64016e-15, No Iterations 1
DILUPBiCG: Solving for taufirstxy, Initial residual = 0.00719778, Final residual = 1.69566e-15, No Iterations 1
DILUPBiCG: Solving for taufirstxz, Initial residual = 0.00372445, Final residual = 1.81474e-17, No Iterations 1
DILUPBiCG: Solving for taufirstyy, Initial residual = 0.00513511, Final residual = 2.97488e-15, No Iterations 1
DILUPBiCG: Solving for taufirstyz, Initial residual = 0.00372444, Final residual = 2.90091e-18, No Iterations 1
DILUPBiCG: Solving for taufirstzz, Initial residual = 0.00360069, Final residual = 9.85626e-17, No Iterations 1
Model mode 2
DILUPBiCG: Solving for tausecondxx, Initial residual = 0.00901374, Final residual = 4.5788e-16, No Iterations 1
DILUPBiCG: Solving for tausecondxy, Initial residual = 0.011415, Final residual = 3.71279e-16, No Iterations 1
DILUPBiCG: Solving for tausecondxz, Initial residual = 0.00373582, Final residual = 1.74955e-17, No Iterations 1
DILUPBiCG: Solving for tausecondyy, Initial residual = 0.00924354, Final residual = 6.99518e-16, No Iterations 1
DILUPBiCG: Solving for tausecondyz, Initial residual = 0.00373581, Final residual = 1.75101e-17, No Iterations 1
DILUPBiCG: Solving for tausecondzz, Initial residual = 0.00294321, Final residual = 5.88967e-17, No Iterations 1
Model mode 3
DILUPBiCG: Solving for tauthirdxx, Initial residual = 0.00929762, Final residual = 1.30313e-16, No Iterations 1
DILUPBiCG: Solving for tauthirdxy, Initial residual = 0.0117061, Final residual = 4.89053e-17, No Iterations 1
DILUPBiCG: Solving for tauthirdxz, Initial residual = 0.00373792, Final residual = 1.78278e-17, No Iterations 1
DILUPBiCG: Solving for tauthirdyy, Initial residual = 0.00953793, Final residual = 1.59044e-16, No Iterations 1
DILUPBiCG: Solving for tauthirdyz, Initial residual = 0.00373792, Final residual = 1.9548e-17, No Iterations 1
DILUPBiCG: Solving for tauthirdzz, Initial residual = 0.0026507, Final residual = 5.17534e-18, No Iterations 1
Model mode 4
DILUPBiCG: Solving for taufourthxx, Initial residual = 0.00940334, Final residual = 3.38134e-17, No Iterations 1
DILUPBiCG: Solving for taufourthxy, Initial residual = 0.0118159, Final residual = 1.53916e-17, No Iterations 1
DILUPBiCG: Solving for taufourthxz, Initial residual = 0.00373861, Final residual = 7.48391e-18, No Iterations 1
DILUPBiCG: Solving for taufourthyy, Initial residual = 0.00964937, Final residual = 8.37758e-17, No Iterations 1
DILUPBiCG: Solving for taufourthyz, Initial residual = 0.00373861, Final residual = 1.28578e-17, No Iterations 1
DILUPBiCG: Solving for taufourthzz, Initial residual = 0.00246207, Final residual = 8.77819e-17, No Iterations 1
DILUPBiCG: Solving for T, Initial residual = 0.45522, Final residual = 7.40274e-09, No Iterations 5
DILUPBiCG: Solving for Tw, Initial residual = 0.0828233, Final residual = 1.66062e-08, No Iterations 4
Floating point exception (core dumped)

CHECKMESH :

Create time

Create polyMesh for time = 0

Time = 0

Mesh stats
all points: 222101
live points: 222101
all faces: 654000
live faces: 654000
internal faces: 642000
cells: 216000
boundary patches: 3
point zones: 0
face zones: 0
cell zones: 0

Overall number of cells of each type:
hexahedra: 216000
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.
Face vertices OK.
Number of regions: 1 (OK).

Checking patch topology for multiply connected surfaces ...
Patch Faces Points Area [m^2] Surface topology 
inlet 3600 3641 0.00196148 ok (non-closed singly connected) 
outlet 3600 3641 0.00196148 ok (non-closed singly connected) 
pipewall 4800 4880 0.392598 ok (non-closed singly connected) 

Checking geometry...
This is a 3-D mesh
Overall domain bounding box (-0.025 -0.025 0) (0.025 0.025 2.5)
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 (2.02337e-16 2.16504e-16 4.25812e-17) Threshold = 1e-06 OK.
Max cell openness = 2.74096e-16 OK.
Max aspect ratio = 195.315 OK.
Minumum face area = 3.67922e-07. Maximum face area = 8.17913e-05. Face area magnitudes OK.
Min volume = 1.53301e-08. Max volume = 2.95413e-08. Total volume = 0.00490369. Cell volumes OK.
Mesh non-orthogonality Max: 37.1451 average: 5.71625 Threshold = 70
Non-orthogonality check OK.
Face pyramids OK.
Max skewness = 0.569773 OK.

Mesh OK.

CONTROL DICT:
startFrom startTime;

startTime 0.0;

stopAt endTime;

endTime 2;

deltaT 1e-16;

writeControl adjustableRunTime;

writeInterval 1;

purgeWrite 0;

writeFormat ascii;

writePrecision 6;

writeCompression uncompressed;

timeFormat general;

timePrecision 6;

graphFormat raw;

runTimeModifiable yes;

adjustTimeStep on;

maxCo 0.25;

maxDeltaT 0.001;

[Grace1]

Dear Sita


Firstly, thank you for your response


Yes I did try it on the Giesekus tutorial geomerty and it gave me the same error

Courant Number mean: 0.000545927 max: 0.292199 velocity magnitude: 0.197535
deltaT = 4.2993e-05
Time = 0.000197973

BiCGStab:  Solving for Ux, Initial residual = 1, Final residual = 1.44448e-27, No Iterations 1
BiCGStab:  Solving for Uy, Initial residual = 1, Final residual = 1.65226e-25, No Iterations 1
CholeskyCG:  Solving for p, Initial residual = 0.99999, Final residual = 9.58303e-08, No Iterations 131
time step continuity errors : sum local = 2.33923e+87, global = 6.5963e+74, cumulative = 6.5963e+74
Model mode 1
BiCGStab:  Solving for taufirstxx, Initial residual = 1, Final residual = 2.87295e-11, No Iterations 2
BiCGStab:  Solving for taufirstxy, Initial residual = 1, Final residual = 1.65959e-08, No Iterations 1
BiCGStab:  Solving for taufirstyy, Initial residual = 1, Final residual = 5.09339e-07, No Iterations 1
BiCGStab:  Solving for taufirstzz, Initial residual = 0, Final residual = 0, No Iterations 0
Model mode 2
BiCGStab:  Solving for tausecondxx, Initial residual = 1, Final residual = 2.87303e-11, No Iterations 2
BiCGStab:  Solving for tausecondxy, Initial residual = 1, Final residual = 1.6596e-08, No Iterations 1
BiCGStab:  Solving for tausecondyy, Initial residual = 1, Final residual = 5.09339e-07, No Iterations 1
BiCGStab:  Solving for tausecondzz, Initial residual = 0, Final residual = 0, No Iterations 0
Model mode 3
BiCGStab:  Solving for tauthirdxx, Initial residual = 1, Final residual = 2.87304e-11, No Iterations 2
BiCGStab:  Solving for tauthirdxy, Initial residual = 1, Final residual = 1.6596e-08, No Iterations 1
BiCGStab:  Solving for tauthirdyy, Initial residual = 1, Final residual = 5.09339e-07, No Iterations 1
BiCGStab:  Solving for tauthirdzz, Initial residual = 0, Final residual = 0, No Iterations 0
Model mode 4
BiCGStab:  Solving for taufourthxx, Initial residual = 1, Final residual = 2.87304e-11, No Iterations 2
BiCGStab:  Solving for taufourthxy, Initial residual = 1, Final residual = 1.6596e-08, No Iterations 1
BiCGStab:  Solving for taufourthyy, Initial residual = 1, Final residual = 5.09339e-07, No Iterations 1
BiCGStab:  Solving for taufourthzz, Initial residual = 0, Final residual = 0, No Iterations 0
Floating point exception (core dumped)

For the pipe geometry mesh file that I used: Tw - wall temperature & T- fluid temperature


this is the first mesh that I tried

scale   0.025;

vertices
(
    
    //block0 vertices
    (-0.25 0.25 0)            //0
    (-0.707106 0.707106 0)    //1
    (0.707106 0.707106 0)     //2
    (0.25 0.25 0)             //3
    (-0.25 0.25 100)          //4
    (-0.707106 0.707106 100)  //5
    (0.707106 0.707106 100)   //6
    (0.25 0.25 100)           //7

    //block1 new vertices
    (0.25 -0.25 0)            //8
    (0.707106 -0.707106 0)    //9
    (0.25 -0.25 100)          //10
    (0.707106 -0.707106 100)  //11

    //block3 new vertices
    (-0.25 -0.25 0)           //12
    (-0.707106 -0.707106 0)   //13
    (-0.25 -0.25 100)         //14
    (-0.707106 -0.707106 100) //15
);

xcells 20;
ycells 40;
zcells 60;
xcells1 20;
ycells1 20;
zcells1 60;


stretch 0.25;


blocks
(
    //block0
    hex (0 3 2 1 4 7 6 5)       ($xcells $ycells $zcells)    simpleGrading (1 $stretch 1)
    //block1
    hex (3 8 9 2 7 10 11 6)     ($xcells $ycells $zcells)    simpleGrading (1 $stretch 1)
    //block2
    hex (8 12 13 9 10 14 15 11) ($xcells $ycells $zcells)    simpleGrading (1 $stretch 1)
    //block3
    hex (12 0 1 13 14 4 5 15)   ($xcells $ycells $zcells)    simpleGrading (1 $stretch 1)
    //block4
    hex (0 12 8 3 4 14 10 7)    ($xcells1 $ycells1 $zcells1) simpleGrading (1 1 1)
);

edges
(
    //block0 arc
    arc 1 2 (0 1 0)
    arc 5 6 (0 1 100)
    //block1 arc
    arc 2 9 (1 0 0)
    arc 6 11 (1 0 100)
    //block2 arc
    arc 9 13 (0 -1 0)
    arc 11 15 (0 -1 100)
    //block3 arc
    arc 1 13 (-1 0 0)
    arc 5 15 (-1 0 100)

);

boundary
(
    inlet
    {
     type patch;
         faces
         (
              (0 1 2 3)
              (2 3 8 9)
              (8 9 13 12)
              (13 12 0 1)
              (0 3 8 12)
         );
     }
    outlet
    { 
         type patch;
         faces
         (
             (4 5 6 7)
             (6 7 10 11)
             (15 11 10 14)
             (15 14 4 5)
             (4 7 10 14)
         );
    }
    pipewall
    {
       type wall;
       faces
       (
           (1 5 6 2)
           (2 6 11 9)
           (9 11 15 13)
           (13 15 5 1)
      );
    }
);

mergePatchPairs
(
);

// ************************************************************************* //

which gave me the above output. Tried to modify the mesh by reducing the stretching and the length of the pipe but got the same error

Boundary conditions:

    object      U;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions      [0 1 -1 0 0 0 0];

internalField   uniform (0 0 0);

boundaryField
{
    inlet
    {
        type            fixedValue;
        value           uniform (0 0 0.336);
    }
    pipewall
    {
        type            fixedValue;
        value           uniform (0 0 0);
    }
    outlet
    {
        type            zeroGradient;
    }
    
}

 class       volScalarField;
    object      T;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions      [0 0 0 1 0 0 0];

internalField   uniform 200;

boundaryField
{
    inlet
    {
        type            fixedValue;
        value           uniform 100;
    }

    pipewall
    {
        type            zeroGradient;
    }

   outlet
    {
        type            zeroGradient;
        
    }

}

 class       volScalarField;
    object      Tw;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions      [0 0 0 1 0 0 0];

internalField   uniform 150;

boundaryField
{
     inlet
    {
        type            zeroGradient;
    }

    pipewall
    {
        type            zeroGradient;
    }

   outlet
    {
        type            zeroGradient;
        
    }

}

boundary conditions for tau , tau first to forth, N1,N2 and p those I did not change, are exactly as what they have in the tutorial.


fvSchemes

ddtSchemes
{
    default         Euler;
}

gradSchemes
{
    default         Gauss linear;
    grad(p)         Gauss linear;
    grad(U)         Gauss linear;
}

divSchemes
{
    default                  none;
    div(phi,U)               Gauss upwind;
    div(((rho*Cp)*phi),T)    Gauss upwind;

    div(phi,taufirst)          Gauss upwind;
    div(phi,tausecond)         Gauss upwind;
    div(phi,tauthird)          Gauss upwind;
    div(phi,taufourth)         Gauss upwind;

    div(tau)                 Gauss linear;
    div(phi,k)               Gauss upwind;
}

laplacianSchemes
{
    default                      none;
    
    laplacian(etaPEff,U)         Gauss linear corrected;
    laplacian(etaPEff+etaS,U)    Gauss linear corrected;
    laplacian((1|A(U)),p)        Gauss linear corrected;
    laplacian(k,T)               Gauss linear corrected;
    laplacian(k,Tw)              Gauss linear corrected;
}

interpolationSchemes
{
    default           linear;
    interpolate(HbyA) linear;
}

snGradSchemes
{
    default         corrected;
}

// ************************************************************************* //

solvers
{

    p
    {
         solver          CG;
        preconditioner  Cholesky;

        tolerance        1e-07;
        relTol           0;
        minIter          0;
        maxIter          800;
    }

    T 
    {
       solver           BiCGStab;
        preconditioner   DILU;
        tolerance        1e-7;
        relTol           0;
    };


     Tw 
    {
       solver           BiCGStab;
       preconditioner   DILU;
        tolerance        1e-7;
        relTol           0;
    };


    U
    {

        solver           BiCGStab;
        preconditioner   ILU0;

        tolerance         1e-6;
        relTol            0;
        minIter           0;
        maxIter           1000;
    }

    taufirst
    {
        solver            BiCGStab;
        preconditioner   ILU0;

        tolerance         1e-6;
        relTol            0;
        minIter           0;
        maxIter           1000;
    }

    tausecond
    {
        solver            BiCGStab;
        preconditioner   ILU0;

        tolerance         1e-6;
        relTol            0;
        minIter           0;
        maxIter           1000;
    }

    tauthird
    {
        solver            BiCGStab;
        preconditioner   ILU0;

        tolerance         1e-6;
        relTol            0;
        minIter           0;
        maxIter           1000;
    }

    taufourth
    {
        solver            BiCGStab;
        preconditioner   ILU0;

        tolerance         1e-6;
        relTol            0;
        minIter           0;
        maxIter           1000;
    }

}


PISO
{
    nCorrectors    2;
    nNonOrthogonalCorrectors 0;
    pRefCell        0;
    pRefValue       0;
}

relaxationFactors
{
    p                   0.3;

    U                   0.5;
    T                   0.5;     
    Tw                  0.5;

    taufirst            0.3;
    tausecond           0.3;
    tauthird            0.3;
    taufourth           0.3;

}

Thank you in advance for your assistance and guidance

[alimea]

Originally Posted by Grace1

Hello Everyone

May you kindly assist me,

I am using viscoelasticFluidFoam solver and the Giesekus Model to simulate a flow in a pipe. And have modified both by adding temperature.

Now every time I run my simulation it gives me the below error and have tried to reduce delta T, Max Co. number and even check velocity value but nothing seems to be working

Courant Number mean: 8.19815e-06 max: 0.0016354 velocity magnitude: 0.336024
deltaT = 0.000121669
Time = 0.000730166

DILUPBiCG: Solving for Ux, Initial residual = 0.00475588, Final residual = 9.01518e-08, No Iterations 1
DILUPBiCG: Solving for Uy, Initial residual = 0.00477491, Final residual = 5.60245e-09, No Iterations 1
DILUPBiCG: Solving for Uz, Initial residual = 0.00153646, Final residual = 3.99944e-09, No Iterations 1
DICPCG: Solving for p, Initial residual = 0.202343, Final residual = 9.65702e-08, No Iterations 322
time step continuity errors : sum local = 1.74596e-13, global = -1.10905e-14, cumulative = -1.43122e-14
Model mode 1
DILUPBiCG: Solving for taufirstxx, Initial residual = 0.00504237, Final residual = 2.64016e-15, No Iterations 1
DILUPBiCG: Solving for taufirstxy, Initial residual = 0.00719778, Final residual = 1.69566e-15, No Iterations 1
DILUPBiCG: Solving for taufirstxz, Initial residual = 0.00372445, Final residual = 1.81474e-17, No Iterations 1
DILUPBiCG: Solving for taufirstyy, Initial residual = 0.00513511, Final residual = 2.97488e-15, No Iterations 1
DILUPBiCG: Solving for taufirstyz, Initial residual = 0.00372444, Final residual = 2.90091e-18, No Iterations 1
DILUPBiCG: Solving for taufirstzz, Initial residual = 0.00360069, Final residual = 9.85626e-17, No Iterations 1
Model mode 2
DILUPBiCG: Solving for tausecondxx, Initial residual = 0.00901374, Final residual = 4.5788e-16, No Iterations 1
DILUPBiCG: Solving for tausecondxy, Initial residual = 0.011415, Final residual = 3.71279e-16, No Iterations 1
DILUPBiCG: Solving for tausecondxz, Initial residual = 0.00373582, Final residual = 1.74955e-17, No Iterations 1
DILUPBiCG: Solving for tausecondyy, Initial residual = 0.00924354, Final residual = 6.99518e-16, No Iterations 1
DILUPBiCG: Solving for tausecondyz, Initial residual = 0.00373581, Final residual = 1.75101e-17, No Iterations 1
DILUPBiCG: Solving for tausecondzz, Initial residual = 0.00294321, Final residual = 5.88967e-17, No Iterations 1
Model mode 3
DILUPBiCG: Solving for tauthirdxx, Initial residual = 0.00929762, Final residual = 1.30313e-16, No Iterations 1
DILUPBiCG: Solving for tauthirdxy, Initial residual = 0.0117061, Final residual = 4.89053e-17, No Iterations 1
DILUPBiCG: Solving for tauthirdxz, Initial residual = 0.00373792, Final residual = 1.78278e-17, No Iterations 1
DILUPBiCG: Solving for tauthirdyy, Initial residual = 0.00953793, Final residual = 1.59044e-16, No Iterations 1
DILUPBiCG: Solving for tauthirdyz, Initial residual = 0.00373792, Final residual = 1.9548e-17, No Iterations 1
DILUPBiCG: Solving for tauthirdzz, Initial residual = 0.0026507, Final residual = 5.17534e-18, No Iterations 1
Model mode 4
DILUPBiCG: Solving for taufourthxx, Initial residual = 0.00940334, Final residual = 3.38134e-17, No Iterations 1
DILUPBiCG: Solving for taufourthxy, Initial residual = 0.0118159, Final residual = 1.53916e-17, No Iterations 1
DILUPBiCG: Solving for taufourthxz, Initial residual = 0.00373861, Final residual = 7.48391e-18, No Iterations 1
DILUPBiCG: Solving for taufourthyy, Initial residual = 0.00964937, Final residual = 8.37758e-17, No Iterations 1
DILUPBiCG: Solving for taufourthyz, Initial residual = 0.00373861, Final residual = 1.28578e-17, No Iterations 1
DILUPBiCG: Solving for taufourthzz, Initial residual = 0.00246207, Final residual = 8.77819e-17, No Iterations 1
DILUPBiCG: Solving for T, Initial residual = 0.45522, Final residual = 7.40274e-09, No Iterations 5
DILUPBiCG: Solving for Tw, Initial residual = 0.0828233, Final residual = 1.66062e-08, No Iterations 4
Floating point exception (core dumped)

CHECKMESH :

Create time

Create polyMesh for time = 0

Time = 0

Mesh stats
all points: 222101
live points: 222101
all faces: 654000
live faces: 654000
internal faces: 642000
cells: 216000
boundary patches: 3
point zones: 0
face zones: 0
cell zones: 0

Overall number of cells of each type:
hexahedra: 216000
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.
Face vertices OK.
Number of regions: 1 (OK).

Checking patch topology for multiply connected surfaces ...
Patch Faces Points Area [m^2] Surface topology
inlet 3600 3641 0.00196148 ok (non-closed singly connected)
outlet 3600 3641 0.00196148 ok (non-closed singly connected)
pipewall 4800 4880 0.392598 ok (non-closed singly connected)

Checking geometry...
This is a 3-D mesh
Overall domain bounding box (-0.025 -0.025 0) (0.025 0.025 2.5)
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 (2.02337e-16 2.16504e-16 4.25812e-17) Threshold = 1e-06 OK.
Max cell openness = 2.74096e-16 OK.
Max aspect ratio = 195.315 OK.
Minumum face area = 3.67922e-07. Maximum face area = 8.17913e-05. Face area magnitudes OK.
Min volume = 1.53301e-08. Max volume = 2.95413e-08. Total volume = 0.00490369. Cell volumes OK.
Mesh non-orthogonality Max: 37.1451 average: 5.71625 Threshold = 70
Non-orthogonality check OK.
Face pyramids OK.
Max skewness = 0.569773 OK.

Mesh OK.

CONTROL DICT:
startFrom startTime;

startTime 0.0;

stopAt endTime;

endTime 2;

deltaT 1e-16;

writeControl adjustableRunTime;

writeInterval 1;

purgeWrite 0;

writeFormat ascii;

writePrecision 6;

writeCompression uncompressed;

timeFormat general;

timePrecision 6;

graphFormat raw;

runTimeModifiable yes;

adjustTimeStep on;

maxCo 0.25;

maxDeltaT 0.001;


I am not sure on how else to resolve this issue . May you kindly assist me or provide some guidance on how to resolve this problem


Thanks in advance

Hello Grace

What are the Reynolds number and Deborah number in your case?
The viscoelasticFluidFoam is unstable numerically in high De numbers.
You may use rheoHeatFoam, which is a stable solver of the rheoTool package. It can be download from GitHub:

https://github.com/fppimenta/rheoTool

regards,
Ali

[sita]

Hi Grace,

Hm, in that case I'd go back to the original Gieskus tutorial case, see if you can get that to run, and then take baby steps from there. For example, is there a way to cancel the influence of temperature in your adapted model, say, by choosing the same value for the wall and fluid temperatures? And what happens if you change your BCs to achieve very low Re and Wi numbers, e.g. by setting the inlet velocity to a very low value?
I know this process can be frustrating sometimes, but usually there's a perfectly sensible, usually physical reason that things don't work in OpenFOAM.

Hope this helps,
Sita

EDIT: Another quick test would be to plug in the standard Giesekus model in your pipe flow case. If that works, the problem should be in your implementation of the temperature-dependent Giesekus model, if it blows up as well, the problem is more likely to be in your mesh or BCs.

[Grace1]

Dear Sita and Ali

What are the Reynolds number and Deborah number in your case?

Re is around 500 and De 0.005, I will rework these values . Thank you for this point

Viscoelastic Property:

 type multiMode;

        models
        (
            first
            {
            type Giesekus_WLF;
            rho               rho [1 -3 0 0 0 0 0] 803.87097;
            C1                C1  [0  0 0 0 0 0 0] 17.44;
            C2                C2  [0  0 0 1 0 0 0] 51.6; 
            T0                T0  [0  0 0 1 0 0 0] 100;
            etaS0             etaS0 [1 -1 -1 0 0 0 0] 0.002;
            etaP0             etaP0 [1 -1 -1 0 0 0 0] 0.04;
            lambda0           lambda0 [0 0 1 0 0 0 0] 0.6855;
            alpha             alpha [0 0 0 0 0 0 0] 0.5;
            
            }

            second
            {
            type Giesekus_WLF;
            rho               rho [1 -3 0 0 0 0 0] 803.87097;
            C1                C1  [0  0 0 0 0 0 0] 17.44;
            C2                C2  [0  0 0 1 0 0 0] 51.6; 
            T0                T0  [0  0 0 1 0 0 0] 100;
            etaS0             etaS0 [1 -1 -1 0 0 0 0] 0.002;
            etaP0             etaP0 [1 -1 -1 0 0 0 0] 0.2324;
            lambda0           lambda0 [0 0 1 0 0 0 0] 0.1396;
            alpha             alpha [0 0 0 0 0 0 0] 0.2;
            }

            third
            {
            type Giesekus_WLF;
            rho               rho [1 -3 0 0 0 0 0] 803.87097;
            C1                C1  [0  0 0 0 0 0 0] 17.44;
            C2                C2  [0  0 0 1 0 0 0] 51.6; 
            T0                T0  [0  0 0 1 0 0 0] 100;
            etaS0             etaS0 [1 -1 -1 0 0 0 0] 0.002;
            etaP0             etaP0 [1 -1 -1 0 0 0 0] 0.5664;
            lambda0           lambda0 [0 0 1 0 0 0 0] 0.0389;
            alpha             alpha [0 0 0 0 0 0 0] 0.3;
            }

            fourth
            {
            type Giesekus_WLF;
            rho               rho [1 -3 0 0 0 0 0] 803.87097;
            C1                C1  [0  0 0 0 0 0 0] 17.44;
            C2                C2  [0  0 0 1 0 0 0] 51.6; 
            T0                T0  [0  0 0 1 0 0 0] 100 ;
            etaS0             etaS0 [1 -1 -1 0 0 0 0] 0.002;
            etaP0             etaP0 [1 -1 -1 0 0 0 0] 0.5850;
            lambda0           lambda0 [0 0 1 0 0 0 0] 0.0059;
            alpha             alpha [0 0 0 0 0 0 0] 0.2;
            }

        );

 }

Hm, in that case I'd go back to the original Gieskus tutorial case, see if you can get that to run, and then take baby steps from there. For example, is there a way to cancel the influence of temperature in your adapted model, say, by choosing the same value for the wall and fluid temperatures? And what happens if you change your BCs to achieve very low Re and Wi numbers, e.g. by setting the inlet velocity to a very low value?
I know this process can be frustrating sometimes, but usually there's a perfectly sensible, usually physical reason that things don't work in OpenFOAM.

Okay thank you, I will try this


Another question can my source code add to the problem as well ? I modified the Giesekus Model using WLF model

Thank you for your guidance

[pratyush_6174]

cd openfoam2206/src/transportModels/viscoelastic/&& wmake libso && cd -
wmake libso (viscoelastic)
g++ -std=c++14 -m64 -pthread -DOPENFOAM=2206 -DWM_DP -DWM_LABEL_SIZE=32 -Wall -Wextra -Wold-style-cast -Wnon-virtual-dtor -Wno-unused-parameter -Wno-invalid-offsetof -Wno-attributes -Wno-unknown-pragmas -O3 -DNoRepository -ftemplate-depth-100 -I/usr/lib/openfoam/openfoam2206/src/finiteVolume/lnInclude -iquote. -IlnInclude -I/usr/lib/openfoam/openfoam2206/src/OpenFOAM/lnInclude -I/usr/lib/openfoam/openfoam2206/src/OSspecific/POSIX/lnInclude -fPIC -c viscoelasticModel/viscoelasticModel.C -o Make/linux64GccDPInt32Opt/viscoelasticModel/viscoelasticModel.o
In file included from /usr/lib/openfoam/openfoam2206/src/finiteVolume/lnInclude/lduPrimitiveMeshAssemblyTemplates.C:31,
from /usr/lib/openfoam/openfoam2206/src/finiteVolume/lnInclude/lduPrimitiveMeshAssembly.H:236,
from /usr/lib/openfoam/openfoam2206/src/finiteVolume/lnInclude/fvMatrix.H:54,
from /usr/lib/openfoam/openfoam2206/src/finiteVolume/lnInclude/fvmDdt.H:41,
from /usr/lib/openfoam/openfoam2206/src/finiteVolume/lnInclude/fvm.H:45,
from lnInclude/viscoelasticLaw.H:45,
from viscoelasticModel/viscoelasticModel.H:43,
from viscoelasticModel/viscoelasticModel.C:27:
/usr/lib/openfoam/openfoam2206/src/finiteVolume/lnInclude/cyclicAMIFvPatch.H:42:10: fatal error: cyclicAMILduInterface.H: No such file or directory
42 | #include "cyclicAMILduInterface.H"
| ^~~~~~~~~~~~~~~~~~~~~~~~~
compilation terminated.
make: *** [/usr/lib/openfoam/openfoam2206/wmake/rules/General/transform:35: Make/linux64GccDPInt32Opt/viscoelasticModel/viscoelasticModel.o] Error 1

[Saicharan]

Hi sita,
does openfoam 8 has any solver like viscoElasticFluidfoam?

[sita]

Hi,

Sorry, I haven't used OpenFOAM in a while, so I wouldn't know for sure. As far as I'm aware, you need foamExtend to run viscoelasticFluidFoam.
If you take a look at the standard solvers in the the OpenFOAM-8 user guide, you can see that there's nonNewtonianIcoFoam, which might suit your needs:
https://doc.cfd.direct/openfoam/user...andard-solvers
I never tried this solver myself, but you could take a look at that as well.

Good luck,
Sita

[saicharan662000@gmail.com]

Hi sita,
Can i know which version has viscoelasticfluidfoam?

[sita]

Hi Hari,

As I wrote earlier, I haven't used viscoelasticFluidFoam in a while (since 2015!), so I wouldn't know. Have you tried an online search? I just did, and the first hit I got is:
https://sourceforge.net/projects/vffof21x/
So apparently they've moved from foamExtend to OpenFOAM-2.1.x (that's the commercial version if I'm correct, to be found under openfoam.com instead of openfoam.org).
I'm afraid I can't help you any further with this.

Sita

[saicharan662000@gmail.com]

Thank you for the reply sita. I will look into it