Reply To: Point-by-point field – pressure( density ) free energy boundary condition in 3D

[araeli]

Dear Sam,

1) Thank you for your suggestion regarding the convergence criterion. I will try this approach as I am still determining the best method for my specific physical problem.

2a-b) I set the density (and I believe the label is correct) using the following:

    setFreeEnergyInletBoundary<T,DESCRIPTOR>(sLattice1,omega,superGeometry,3,"density",1);
    setFreeEnergyOutletBoundary<T,DESCRIPTOR>(sLattice1,omega,superGeometry,4,"density",1);

    setFreeEnergyInletBoundary<T,DESCRIPTOR>(sLattice2,omega,superGeometry,3,"density",2);
    setFreeEnergyOutletBoundary<T,DESCRIPTOR>(sLattice2,omega,superGeometry,4,"density",2);

However, the boundary values are not being enforced as expected. For example, in a piston-like simulation, I tried setting an inlet density of 10 (non-physical, just for visualization purposes in Paraview), like so:

  AnalyticalConst3D<T,T> rhoinVal( inletDensity );
        AnalyticalConst3D<T, T> rhooutVal(T {1});
        AnalyticalConst3D<T,T> phiminusone( T {-1} );
        AnalyticalConst3D<T, T> phione(T {1});
        sLattice1.defineRho(superGeometry,3,rhoinVal);
        sLattice1.defineRho(superGeometry,3,rhooutVal);

        sLattice2.defineRho(superGeometry,3,phiminusone);//3 inlet material number
        sLattice2.defineRho(superGeometry,4,phione);// 4 outlet material number

        sLattice1.setProcessingContext<Array<momenta::FixedDensity::RHO>>(
                    ProcessingContext::Simulation);
        sLattice2.setProcessingContext<Array<momenta::FixedDensity::RHO>>(
                    ProcessingContext::Simulation);

I expected a rho value of 10 at the output, but it seems the boundary condition is not applied. I tried setting this before the coupling definitions, after them, and in the simulation loop, but without success.

I defined the couplings in the order: outlet, chemicalPotential, force, and inlet, as shown below:

    SuperLatticeCoupling coupling1(
                InletOutletCoupling3D{},
                names::A{}, sLattice2,
                names::B{}, sLattice1
                );

    coupling1.restrictTo(superGeometry.getMaterialIndicator({4}));

    SuperLatticeCoupling coupling2(
                ChemicalPotentialCoupling3D{},
                names::A{}, sLattice1,
                names::B{}, sLattice2);

    coupling2.template setParameter<ChemicalPotentialCoupling3D::ALPHA>(alpha);
    coupling2.template setParameter<ChemicalPotentialCoupling3D::KAPPA1>(kappa1);
    coupling2.template setParameter<ChemicalPotentialCoupling3D::KAPPA2>(kappa2);
    coupling2.restrictTo(superGeometry.getMaterialIndicator({1}));

    SuperLatticeCoupling coupling3(
                ForceCoupling3D{},
                names::A{}, sLattice2,
                names::B{}, sLattice1);

    coupling3.restrictTo(superGeometry.getMaterialIndicator({1}));

    ///inlet coupling
    SuperLatticeCoupling coupling4(
                InletOutletCoupling3D{},
                names::A{}, sLattice2,
                names::B{}, sLattice1
                );
    coupling4.restrictTo(superGeometry.getMaterialIndicator({3}));

Thank you for your suggestions. I hope the attached code provides some helpful context. I am sure that I am missing something fundamental, but I am struggling to identify exactly what it is.

Best regards,
Alice