[flowlinux]

Hi,

I would like to write the following time derivative during run time.
d/dt (U)
Therefore I suppose I should use the coded functionobject (in controlDict) but unfortunately I'm not able to write the code (yet). I'm doing two phase simulations with interFoam. could anyone help me?

functions
{
    deriv_rhoU
    {
    functionObjectLibs ("libutilityFunctionObjects.so");
    type coded;
    redirectType deriv_rhoU;
    outputControl timeStep;
    code
    #{
tobecompleted
    #};
    } 
}

thank you

[agustinvo]

Hello

more than coding like this, why don't you create a functionObject for that? Take a look to the grad one, and modify it as you need.

[flowlinux]

Hi,

Agustinvo, that doesn't seem any easier to be honest
Anyway, this is my first guess.

   
functions
{
    deriv_rhoU
    {
    functionObjectLibs ("libutilityFunctionObjects.so");
    type coded;
    name test;
    writeControl timeStep;      
    codeWrite
    #{
        const volVectorField& U = mesh().lookupObject<volVectorField>("U");
        const volScalarField& rho = mesh().lookupObject<volScalarField>("rho");

        volVectorField ddt
        (
        IOobject
        (
        "ddt",
        mesh().time().timeName(),
        mesh,
        IOobject::NO_READ,
        IOobject::AUTO_WRITE
        ),
        ddt == fvc::ddt(rho,U);
        );
    #};
    } 
}

[flowlinux]

Hi,

The following code worked for me (version 4.1)

functions
{
    test
    {
    functionObjectLibs ("libutilityFunctionObjects.so");
    type coded;
    name test;
    writeControl writeTime;      
    codeWrite
    #{
    
    const volVectorField& U = mesh().lookupObject<volVectorField>("U");
    const volScalarField& K = mesh().lookupObject<volScalarField>("interfaceProperties:K");
    const volScalarField& rho = mesh().lookupObject<volScalarField>("rho");

        // Write
        volVectorField t("ddt(rho,U)", fvc::ddt(rho,U));
        K.write();
        t.write();
    #};
    } 
}

[zeinelserfy]

Originally Posted by flowlinux

Hi,

The following code worked for me (version 4.1)

functions
{
    test
    {
    functionObjectLibs ("libutilityFunctionObjects.so");
    type coded;
    name test;
    writeControl writeTime;      
    codeWrite
    #{
    
    const volVectorField& U = mesh().lookupObject<volVectorField>("U");
    const volScalarField& K = mesh().lookupObject<volScalarField>("interfaceProperties:K");
    const volScalarField& rho = mesh().lookupObject<volScalarField>("rho");

        // Write
        volVectorField t("ddt(rho,U)", fvc::ddt(rho,U));
        K.write();
        t.write();
    #};
    } 
}

@ flowlinux

does this function work properly?
you just add it inside the controlDict, right?
the name of the variable is t?