[Andre1742]

Hy everyone,

I am trying to run a simulatin of a car carrier truck. Everything seems to be pretty straightforward, but I am having an hard time in controlling file generations.

I started from the motorbike tut, and then I changed whatever I needed, including the addition of a force function. I cannot understand why I keep having my force and moment files generated in each processor folder, while it doesnt happen for the forcecoeffs, which are instead controlled my my control dict.
Here are my function and controldict:



/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: v2306 |
| \\ / A nd | Website: www.openfoam.com |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class dictionary;
object controlDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

application simpleFoam;

startFrom latestTime;

startTime 0;

stopAt endTime;

endTime 10; //almeno 5000 prima era 2000

deltaT 1;

writeControl timeStep;

writeInterval 300;

purgeWrite 2;

writeFormat ascii;

writePrecision 6;

writeCompression off;

timeFormat general;

timePrecision 6;

runTimeModifiable true;

functions
{
// Include additional function objects if necessary
#include "streamLines"
#include "wallBoundedStreamLines"
#include "cuttingPlane"
#include "forceCoeffs"
#include "force"


yPlus
{
type yPlus;
libs (fieldFunctionObjects);
writeControl timeStep; // Changed to timeStep for consistency with writeInterval
writeInterval 200; // Make sure this matches with the frequency you want to write yPlus
purgeWrite 2;

patches
(
Bisarca
lowerWall
);
}



fieldAverage1
{
type fieldAverage;
libs (fieldFunctionObjects);
writeControl writeTime;

fields
(
U
{
mean on;
prime2Mean on;
base time;
timeStart -2000; // Start averaging from the latest time
timeEnd -3000; // End averaging 1000 iterations ago
}

p
{
mean on;
prime2Mean on;
base time;
timeStart -2000; // Start averaging from the latest time
timeEnd -3000; // End averaging 1000 iterations ago
}
);
}


solverInfo
{
type solverInfo;
libs ("libutilityFunctionObjects.so");
fields (p U k omega);
writeResidualFields no;
writeControl timeStep;
writeInterval 200;
}
}


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



/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: v2306 |
| \\ / A nd | Website: www.openfoam.com |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/

force1
{
type forces;

libs (forces);

writeControl timeStep;
timeInterval 1;

log yes;
patches (BisarcaGroup);
p p;
U U;
rho rho;
porosity no;
rho rhoInf; // Indicates incompressible
writeFields yes;
log true;
rhoInf 1; // Redundant for incompressible

CofR (0 0 0); // Rotation around centre line of propeller
pitchAxis (0 1 0);
}


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





/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: v2306 |
| \\ / A nd | Website: www.openfoam.com |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/

forceCoeffs1
{
type forceCoeffs;

libs (forces);

writeControl timeStep;
timeInterval 1;

log yes;

patches (BisarcaGroup);
rho rhoInf; // Indicates incompressible
rhoInf 1; // Required when rho = rhoInf
liftDir (0 0 1);
dragDir (1 0 0);
CofR (0.72 0 0); // Axle midpoint on ground
pitchAxis (0 1 0);
magUInf 20;
lRef 1.42; // Wheelbase length
Aref 1; // mantengo Aref uguale per tutte le configurazioni,a=1 cda
}





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




Thank you all!!!!

[Yann]

Hello Andrea,

This is due to this line which writes the force and moment fields:

writeFields yes;

https://doc.openfoam.com/2306/tools/...forces/forces/

Cheers,
Yann

[Andre1742]

Thank you!
It worked.

Please, could you also take a look to my yPlus function? it does the same but there is no writeFields.

/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: v2306 |
| \\ / A nd | Website: www.openfoam.com |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/

yPlus1
{
type yPlus;

libs (fieldFunctionObjects);

writeControl timeStep;
timeInterval 1;


patches (Bisarca);

}


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


Thank you again!!
Regards

[Yann]

Adjust your writeControl in order to only write the fields each time your are writing the other variables:

writeControl writeTime;
writeInterval 1;

Yann

[Andre1742]

It works!

Thank you!!!

[Andre1742]

Hy everybody,

I am facing a problem still related to my functons.

I would like to simulate a car-carrier truck. Especially, I think it would be really interesting to plot the cumulative Cd, in order to see which part of my model contributes more to the drag force.

I read that it is possible by slighting modify the forcecoeffs. That is what I did, I added the following part:
binData
{
nBin 50;
direction (1 0 0);
cumulative yes;
}

As a result, nothing changed compared to when I was not interested to the cumulative(output did not changed).

So this is my forcecoeffs:

/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: v2306 |
| \\ / A nd | Website: www.openfoam.com |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/

forceCoeffscum1
{
type forceCoeffs;

libs (forces);

writeControl timeStep;
timeInterval 1;

log yes;

patches (Motrice Trailer Macchina1 Macchina2 Macchina3 Macchina4 Macchina5 Macchina6 Macchina7 Ruota1 Ruota2 Ruota3 Ruota4 Ruota5 Ruota6 Ruota7 Ruota8);
rho rhoInf; // Indicates incompressible
rhoInf 1.225; // Required when rho = rhoInf
liftDir (0 0 1);
dragDir (1 0 0);
CofR (0.72 0 0); // Axle midpoint on ground
pitchAxis (0 1 0);
magUInf 20;
lRef 1.42; // Wheelbase length
Aref 8.418259; // mantengo Aref uguale per tutte le configurazioni,a=1 cda

binData
{
nBin 50;
direction (1 0 0);
cumulative yes;
}
}


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


which gives me something like this as output:

# Force and moment coefficients
# dragDir : (1.000000e+00 0.000000e+00 0.000000e+00)
# sideDir : (0.000000e+00 1.000000e+00 0.000000e+00)
# liftDir : (0.000000e+00 0.000000e+00 1.000000e+00)
# rollAxis : (1.000000e+00 0.000000e+00 0.000000e+00)
# pitchAxis : (0.000000e+00 1.000000e+00 0.000000e+00)
# yawAxis : (0.000000e+00 0.000000e+00 1.000000e+00)
# magUInf : 2.000000e+01
# lRef : 1.420000e+00
# Aref : 8.418259e+00
# CofR : (7.200000e-01 0.000000e+00 0.000000e+00)
#
# Time Cd Cd(f) Cd(r) Cl Cl(f) Cl(r) CmPitch CmRoll CmYaw Cs Cs(f) Cs(r)
1 1.743486e+00 -2.461253e+00 4.204739e+00 -3.678612e-02 2.280931e+00 -2.317718e+00 2.299324e+00 -3.332996e+00 6.761764e+00 1.854698e+00 7.689113e+00 -5.834415e+00
2 1.379392e+00 -3.091395e+00 4.470787e+00 7.622977e-03 1.370568e+00 -1.362945e+00 1.366757e+00 -3.781091e+00 8.220369e+00 2.110245e+00 9.275492e+00 -7.165247e+00
3 1.128918e+00 -3.194860e+00 4.323778e+00 4.493676e-02 6.254805e-01 -5.805438e-01 6.030121e-01 -3.759319e+00 8.585122e+00 2.100171e+00 9.635208e+00 -7.535037e+00
4 1.046904e+00 -3.120372e+00 4.167277e+00 6.723828e-02 1.929156e-01 -1.256773e-01 1.592965e-01 -3.643825e+00 8.490653e+00 2.031377e+00 9.506342e+00 -7.474965e+00
5 1.045210e+00 -3.013119e+00 4.058329e+00 8.930964e-02 -9.387154e-02 1.831812e-01 -1.385264e-01 -3.535724e+00 8.261301e+00 1.967062e+00 9.244832e+00 -7.277770e+00
6 1.062146e+00 -2.883361e+00 3.945507e+00 1.103756e-01 -3.002359e-01 4.106115e-01 -3.554237e-01 -3.414434e+00 8.027046e+00 1.897840e+00 8.975966e+00 -7.078126e+00
7 1.083113e+00 -2.746025e+00 3.829138e+00 1.374777e-01 -4.808105e-01 6.182882e-01 -5.495494e-01 -3.287582e+00 7.779906e+00 1.827366e+00 8.693589e+00 -6.866223e+00
8 1.105770e+00 -2.620760e+00 3.726529e+00 1.601435e-01 -5.705205e-01 7.306640e-01 -6.505922e-01 -3.173644e+00 7.570221e+00 1.764757e+00 8.452599e+00 -6.687842e+00
9 1.108024e+00 -2.534941e+00 3.642965e+00 1.768012e-01 -6.133419e-01 7.901430e-01 -7.017425e-01 -3.088953e+00 7.412725e+00 1.718805e+00 8.272127e+00 -6.553322e+00



Instead, I was expecting something like cd related to the different part of my model along the x direction!

Am I doing something wrong?

Thanks to everybody!!!!

[Yann]

Hello,

In the OpenCFD branch (openfoam.com), binData feature has been deprecated and moved into a new function object in OpenFOAM-v2206. If you are using v2206 or newer, you should use the binField function instead:
https://www.openfoam.com/news/main-n...ssing#binfield

For people using the foundation branch (openfoam.org), the binData feature did not change and is still in use in OpenFOAM-12.

Cheers,
Yann

[Andre1742]

Thank you, your answer was really helpful.


Considering these as the patches I have defined:

Motrice{
level (5 6);
patchInfo{
type wall;
}
}
Trailer{
level (5 6);
patchInfo{
type wall;
}
}

Macchina1{
level (5 6);
patchInfo{
type wall;
}
}
Macchina2{
level (5 6);
patchInfo{
type wall;
}
}

Macchina3{
level (5 6);
patchInfo{
type wall;
}
}
Macchina4{
level (5 6);
patchInfo{
type wall;

}
}
Macchina5{
level (5 6);
patchInfo{
type wall;

}
}
Macchina6{
level (5 6);
patchInfo{
type wall;

}
}
Macchina7{
level (5 6);
patchInfo{
type wall;

}
}
Ruota1{
level (5 6);
patchInfo{
type wall;
}
}
Ruota2{
level (5 6);
patchInfo{
type wall;
}
}
Ruota3{
level (5 6);
patchInfo{
type wall;
}
}
Ruota4{
level (5 6);
patchInfo{
type wall;
}
}
Ruota5{
level (5 6);
patchInfo{
type wall;
}
}
Ruota6{
level (5 6);
patchInfo{
type wall;
}
}
Ruota7{
level (5 6);
patchInfo{
type wall;
}
}
Ruota8{
level (5 6);
patchInfo{
type wall;
}
}



do you think this function is well defined?

/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: v2306 |
| \\ / A nd | Website: www.openfoam.com |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/

forceCoeffs1
{
type forceCoeffs;

libs (forces);

writeControl timeStep;
timeInterval 1;

log yes;

patches (Motrice Trailer Macchina1 Macchina2 Macchina3 Macchina4 Macchina5 Macchina6 Macchina7 Ruota5 Ruota6 Ruota7 Ruota8);
rho rhoInf; // Indicates incompressible
rhoInf 1.225; // Required when rho = rhoInf
liftDir (0 0 1);
dragDir (1 0 0);
CofR (0.72 0 0); // Axle midpoint on ground
pitchAxis (0 1 0);
magUInf 20;
lRef 1.42; // Wheelbase length
Aref 8.418259; // mantengo Aref uguale per tutte le configurazioni,a=1 cda
}

binField1
{
type binField;
libs (fieldFunctionObjects);
binModel singleDirectionUniformBin;
fields (forceCoeff);
patches (Motrice Trailer Macchina1 Macchina2 Macchina3 Macchina4 Macchina5 Macchina6 Macchina7 Ruota5 Ruota6 Ruota7 Ruota8);
decomposePatchValues yes;
CofR (0.72 0 0); // Axle midpoint on ground
//cellZones (porousZone);

binData
{
nBin 30; // output data into 20 bins
direction (1 0 0); // bin direction
cumulative yes;
}
writeControl writeTime;
}
// ************************************************** *********************** //

I just reported as patches the parts that are not cut out by the symmetry condition. I am not sure about the meaning of cellZones (porousZone); Do i need it?

Additionaly, the results it gaves me, in terms of x values, are related to my whole blockmesh domain or just my model?


Thank you for your answer again and for being so helpful!!!!!!

[Yann]

Hi Andrea,

I don't think you need the cellZone entry.
The bins should be calculated based on your patches, so you will have 30 bins evenly distributed along the x axis based on the patch list you defined.
You can check the coordinates of the bins in the result file.

Yann

[Andre1742]

Thank you again Yann,
your answer are always really appreciated!