Commit aa5951f5 authored by Dennis Gläser's avatar Dennis Gläser Committed by Timo Koch
Browse files

[facet][box][darcyslaw] use tpfa flux on interior boundaries

This way we can formulate the flux dependent on both the matrix as
well as the facet permeability. This significantly reduces the condition
number of the resulting matrix and thus improves newton convergence.
parent 89a198f5
......@@ -91,35 +91,56 @@ public:
// on interior Neumann boundaries, evaluate the flux using the facet permeability
if (bcTypes.hasOnlyNeumann())
{
// interpolate pressure/density to scvf integration point
Scalar p = 0.0;
// compute point on element whose connection vector to
// the scvf integration point is parallel to the normal
const auto& elemGeometry = element.geometry();
const auto d1 = scvf.ipGlobal() - insideScv.dofPosition();
const auto d2 = elemGeometry.center() - insideScv.dofPosition();
const auto d1Norm = d1.two_norm();
const auto d2Norm = d2.two_norm();
using std::tan;
using std::acos;
const auto angle = acos( (d1*d2)/d1Norm/d2Norm );
const auto dm = tan(angle)*d1Norm;
auto pos = scvf.unitOuterNormal();
pos *= -1.0*dm;
pos += scvf.ipGlobal();
const auto posLocal = elemGeometry.local(pos);
std::vector< Dune::FieldVector<Scalar, 1> > insideShapeValues;
fvGeometry.fvGridGeometry().feCache().get(elemGeometry.type()).localBasis().evaluateFunction(posLocal, insideShapeValues);
Scalar rho = 0.0;
Scalar pInside = 0.0;
for (const auto& scv : scvs(fvGeometry))
{
const auto& volVars = elemVolVars[scv];
p += volVars.pressure(phaseIdx)*shapeValues[scv.indexInElement()][0];
rho += volVars.density(phaseIdx)*shapeValues[scv.indexInElement()][0];
pInside += volVars.pressure(phaseIdx)*insideShapeValues[scv.indexInElement()][0];
}
// compute tpfa flux from integration point to facet centerline
// compute tpfa flux such that flux and pressure continuity holds
const auto& facetVolVars = problem.couplingManager().getLowDimVolVars(element, scvf);
// On surface grids, use sqrt of aperture as distance measur
using std::sqrt;
// If this is a surface grid, use the square root of the facet extrusion factor
// as an approximate average distance from scvf ip to facet center
using std::sqrt;
const auto a = facetVolVars.extrusionFactor();
auto gradP = scvf.unitOuterNormal();
gradP *= dim == dimWorld ? 0.5*a : 0.5*sqrt(a);
gradP /= gradP.two_norm2();
gradP *= (facetVolVars.pressure(phaseIdx) - p);
const auto df = dim == dimWorld ? 0.5*facetVolVars.extrusionFactor()
: 0.5*sqrt(facetVolVars.extrusionFactor());
const auto tm = 1.0/dm*vtmv(scvf.unitOuterNormal(), insideVolVars.permeability(), scvf.unitOuterNormal());
const auto tf = 1.0/df*vtmv(scvf.unitOuterNormal(), facetVolVars.permeability(), scvf.unitOuterNormal());
auto flux = tm*tf/(tm+tf)*(pInside - facetVolVars.pressure(phaseIdx))
*scvf.area()*insideVolVars.extrusionFactor();
if (enableGravity)
gradP.axpy(-rho, problem.gravityAtPos(scvf.center()));
flux -= rho*scvf.area()*insideVolVars.extrusionFactor()
*vtmv(scvf.unitOuterNormal(), insideVolVars.permeability(), problem.gravityAtPos(scvf.center()));
// apply facet permeability and return the flux
return -1.0*scvf.area()
*insideVolVars.extrusionFactor()
*vtmv(scvf.unitOuterNormal(), facetVolVars.permeability(), gradP);
return flux;
}
// on interior Dirichlet boundaries use the facet pressure and evaluate flux
......
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