[rol97]

Hi everyone,
I am trying to save the residuals of the NS equations in a csv file to be able to easily post process those values.
Right now I am evaluating the residuals by substituting explicitly all the terms and evaluating the value of the equation
e.g.

residual = fvc::ddt(U)+fvc::div(phi, U)- fvc::laplacian(nu, U)+fvc::grad(p)
forAll(mesh.C(),I)
{
    res = residual[I]*residual[I];
} 
finalres = max(res.internalField()).value();

Is there a command line that I can use inside the solver that allows me to write the residual that is usually printed in the log, so that I don't have to manually re-evaluate it?

Thank you in advance.

[mykkujinu2201]

I thought controlDict can help you but it is not.

Sorry.

Add line below before while (runTime.run()) in your main code.

autoPtr<OFstream> residualPtr;

Add line below your calculation of residual.

  // Create the residual file if not already created
   if (residualPtr.empty())
     {
         // File update
         if (Pstream::master())
         {
             fileName residual;
	     word name_ = "residual";
	     
	     // Open new file at start up
	     residualPtr.reset(new OFstream("residual.dat"));
	 }
    }
   
   if (Pstream::master())
     {
       velFilePtr() << runTime.timeName() << tab << residual endl;
     }

Best,
Jun

[rol97]

Thank you very much for your answer, I will try to understand the code and test it.