CFD Online Discussion Forums - why ddt is zero??

The equations are from here

Here is the code:
Code:


// Including necessary class definition and libraries ( Header files )

#include "fvCFD.H"

#include "simpleControl.H"



// handler for printing stuff

#define print(X) Info << X << endl



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



int main(int argc, char *argv[])

{

    // Creating objects from the above defined classes

    // These .H files are basically code snippets ( "inclusion" files )

    #include "setRootCaseLists.H"

    #include "createTime.H"

    #include "createMesh.H"



    simpleControl simple(mesh);



    #include "createFields.H"



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



    Info<< "\nCalculating scalar transport\n" << endl;



    // Trigger the objects to store the old value of theirs at each iteration

    c.oldTime();

    p.oldTime();

    pSt.oldTime();

    // pD.oldTime();

    w.oldTime();

    q.oldTime();



    // Define constant coefficients before the loop to only be calculated once

    dimensionedScalar coeff1 = (Pmi/Pma);

    dimensionedScalar coeff2 = 1e-9 * coeff1 * (VT/De);

    dimensionedScalar coeff3 = -2 * F / CapSt;



    while (simple.loop(runTime))

    {

        Info<< "Time = " << runTime.timeName() << nl << endl;



        #include "CourantNo.H"



        // Potential Equation

        fvScalarMatrix pEqn

            (

             - fvm::laplacian(c, p)

             ==

             coeff2 * fvc::ddt(q)

            );



        pEqn.relax();

        pEqn.solve();



        while (simple.correctNonOrthogonal())

        {

            // Concentration Equation

            fvScalarMatrix cEqn

                (

                 fvm::ddt(c)

                 + coeff_conv * fvm::div(phi, c)

                 - coeff_diff_1 * fvm::laplacian(De, c) // spacer *2 : *0

                 - coeff_diff_2 * fvm::laplacian(De, c) // electrode *0 : *1

                 ==

                 coeff1 * fvc::ddt(w)

                );



            cEqn.relax();

            cEqn.solve();



        }



        q = src_coeff_p * (-c) * exp(Mu) * sinh(pD/VT);

        pSt = coeff3 * q;

        pD = max(-1 * src_coeff_p * p + EV * src_coeff_c - pSt);

        //w = c * exp(Mu) * cosh(pD/VT);

        w = sqrt(q * q + 4 * src_coeff_c * c * c);



        runTime.write();

    }



    Info<< endl;

    Info<< "ExecutionTime = " << runTime.elapsedCpuTime() << " s"

        << "  ClockTime = " << runTime.elapsedClockTime() << " s"

        << nl << endl;



    Info<< "End\n" << endl;



    return 0;
I'm not sure why my source terms are zero :(