[trailer]

Hello,


I would like to create a mixed boundary condition where based, on a switch, I change the boundary from no-slip to slip.


Let's assume that after 1s of simulation the walls go from no slip to slip.



For the time being I have:

myPatch
    {
        type            codedMixed;
        refValue        uniform (0 0 0);
        refGradient     uniform (0 0 0);
        valueFraction   uniform 0;

        name    myBC;   

        code
        #{

        // Access the current value of time
        const Time& time = mesh.time();

        const scalar t = time.value();

        // Loop over the patch
       forAll(patch(), faceI)
        {   

              if(t < 1)
              {
                // Imposes no-slip boundary condition
                  this->refValue()[faceI] = vector::zero; 
                  this->valueFraction()[faceI] = scalar(1); 
              }
              else
              {
                // Imposes slip boundary condition

                 ?Help needed here?

              }
          
        }
      #};
     }

However, I am quite new at this and would appreciate the help.