[EricS]

Hi Foamers!



I'm struggling with a problem which consists in implementing a boundary condtion that changes in time.
I tried to solve this problem using codeStream but, so far, I only ended up with errors and, not being a skillful programmer, I'm stuck here ..


The boundary condition that I'm trying to implement should do what it follows:
1. I impose a value of power (called CPI) which is: CPI = mass_flow_rate * delta_P;
2. I estimate a value of delta_P which becomes delta_P^(1);
3. I compute the resulting mass_flow_rate as: mass_flow_rate^(2) = CPI/delta_P^(1);
4. I use mass_flow_rate^(2) as a boundary condition and I compute delta_P^(2) for that timestep;
5. then I use delta_P^(2) to compute mass_flow_rate^(3) and so on...


I can summarize as mass_flow_rate^(i+1) = CPI/delta_P^(i)


So far I wrote:

throat
    {
    type            flowRateOutletVelocity;
    volumetricFlowRate     #codeStream
        {
            codeInclude
            #{
                #include "fvCFD.H"
            #};

            codeOptions
            #{
                -I$(LIB_SRC)/finiteVolume/lnInclude \
                -I$(LIB_SRC)/meshTools/lnInclude
            #};

            //libs needed to visualize BC in paraview
            codeLibs
            #{
            -lmeshTools \
            -lfiniteVolume
            #};

            code
            #{    
        /* CYCLE EXPLAINED
        input = CPI = massFlowRate * deltaP
        1. massFlowRate = CPI / deltaP;
        2. compute first timestep with the massFlowRate just calculated;
        3. compute deltaP (which is deltaP = p_amb - p_throat = 0 - p_throat = -p_throat);
        4. correct massFlowRate with the new value of p_throat;
        5. keep iterating...
            massFlowRate^(i+1) = - CPI / p_throat^(i)
        */
                const IOdictionary& d = static_cast<const IOdictionary&>
        (
                    dict.parent().parent()
                );
                const fvMesh& mesh = refCast<const fvMesh>(d.db());
                const label id = mesh.boundary().findPatchID("throat");
                const fvPatch& patch = mesh.boundary()[id];
                vectorField U(patch.size(), vector(0, 0, 0));            
        const CPI = 500;                        
                const surfaceVectorField& p = patch().lookupObject("p");    
        const massFlowRate = -CPI/average(p)                
                writeEntry(os,"", massFlowRate);
            #};
        };
    value            uniform (0 0 0);        
    }

but it's only giving me errors...
any tips to make it work?

Thank you in advance!!!