foam-extend4.1-coherent-io/applications/solvers/heatTransfer/buoyantBoussinesqSimpleFoam/UEqn.H

    // Solve the momentum equation

    tmp<fvVectorMatrix> UEqn
    (
        fvm::div(phi, U)
      + turbulence->divDevReff()
    );

    UEqn().relax();

    solve
    (
        UEqn()
      ==
        fvc::reconstruct
        (
            (
                fvc::interpolate(rhok)*(g & mesh.Sf())
              - fvc::snGrad(p)*mesh.magSf()
            )
        )
    );