[Nikhil Bollimuntha]

Hello,

I have been receiving this error while trying to execute the case file for turbulent combustion using the rhoReactingFoam solver.

Screenshot 2019-01-11 at 9.27.08 PM.jpg

Here's the link to the case file:

https://drive.google.com/open?id=1gs...rXX_wkV1GdbGlu

[clapointe]

The output shows you have a problem computing nut (at the boundaries -- line that starts with "#3"). Check your nut boundary conditions.

Caelan

[Nikhil Bollimuntha]

Sir, were you able to have a look at the case files? Because, to the best of my knowledge the boundary conditions I have set are correct.

[clapointe]

I tried to suggest an answer before downloading someone else's case. How about posting your nut text here? Have you compared it to other tutorials that use rans?

Caelan

[Nikhil Bollimuntha]

Here is the nut file sir:

/*--------------------------------*- C++ -*----------------------------------*\
========= |
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration | Website: https://openfoam.org
\\ / A nd | Version: 6
\\/ M anipulation |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class volScalarField;
location "0";
object nut;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions [0 2 -1 0 0 0 0];

internalField uniform 0;

boundaryField
{
fuel-inlet
{
type calculated;
value uniform 0;
}
air-inlet
{
type calculated;
value uniform 0;
}
outlet
{
type calculated;
value uniform 0;
}
upperwall
{
type calculated;
value uniform 0;
}
lowerwall
{
type fixedValue;
value uniform 0;
}
frontandback
{
type empty;
}
}




And to answer your second question, yes sir, I have compared it and to most extent used values from the tutorial cases.

[clapointe]

The error you posted indicated it was a problem with a wall function calculation. However, you are not using wall functions. Did you change it, or are you using wall functions elsewhere?

Caelan

[Nikhil Bollimuntha]

I have used the qRWallFunctionk in the k file and epsilonWallFunction in the epsilon file.

[clapointe]

Not totally sure, but I'd hazard a guess that using those wall functions necessitates using a wall function for nut as well.

Caelan

[Nikhil Bollimuntha]

Just executed the same case by adding wall function to the nut file as well, same error.

[clapointe]

Ok so we've erased one possibility. Given that the simulation immediately crashes, this suspects your initial conditions. Have you tried other values for k and epsilon? Where did you get your current ones?

Caelan

[Nikhil Bollimuntha]

So since you suggested the problem might be with the initial conditions and given that the error indicates that it is with the wall functions, I substituted the wall functions with constant values and now I'm getting another kind of error (attached below)

[clapointe]

It's still a segfault -- looks like a division error. This is often due to division by zero. You can try initializing turbulent fields as very small (but not zero) numbers. Have you looked at the RANS reactingFoam tutorials (https://github.com/OpenFOAM/OpenFOAM...AS/SandiaD_LTS)? For future reference, it's easier to view the code/error if you attach it with the code tags.

Caelan

[Nikhil Bollimuntha]

I'll look into it, and I don't have a RANS reactingFoam tutorial in my tutorials directory, could you please specify which one?

[clapointe]

The link I included is the tutorial. It must have been added for recent OpenFOAM versions.

Caelan