Foam::tmp<Foam::volScalarField> Foam::XiEqModels::basicSubGrid::XiEq() const
{
const fvMesh& mesh = Su_.mesh();
const volVectorField& U = mesh.lookupObject<volVectorField>("U");
const volScalarField& Nv = mesh.lookupObject<volScalarField>("Nv");
const volSymmTensorField& nsv =
mesh.lookupObject<volSymmTensorField>("nsv");
volScalarField magU(mag(U));
volVectorField Uhat
(
U/(mag(U) + dimensionedScalar("Usmall", U.dimensions(), 1e-4))
);
const scalarField Cw = pow(mesh.V(), 2.0/3.0);
tmp<volScalarField> tN
(
new volScalarField
(
IOobject
(
"tN",
mesh.time().constant(),
mesh,
IOobject::NO_READ,
IOobject::NO_WRITE
),
mesh,
dimensionedScalar("zero", Nv.dimensions(), 0.0),
zeroGradientFvPatchVectorField::typeName
)
);
volScalarField& N = tN();
N.internalField() = Nv.internalField()*Cw;
tmp<volSymmTensorField> tns
(
new volSymmTensorField
(
IOobject
(
"tns",
U.mesh().time().timeName(),
U.mesh(),
IOobject::NO_READ,
IOobject::NO_WRITE
),
U.mesh(),
dimensionedSymmTensor
(
"zero",
nsv.dimensions(),
pTraits<symmTensor>::zero
),
zeroGradientFvPatchSymmTensorField::typeName
)
);
volSymmTensorField& ns = tns();
ns.internalField() = nsv.internalField()*Cw;
volScalarField n(max(N - (Uhat & ns & Uhat), scalar(1e-4)));
volScalarField b((Uhat & B_ & Uhat)/sqrt(n));
volScalarField up(sqrt((2.0/3.0)*turbulence_.k()));
volScalarField XiSubEq
(
scalar(1)
+ max(2.2*sqrt(b), min(0.34*magU/up*sqrt(b), scalar(1.6)))
* min(n, scalar(1))
);
return (XiSubEq*XiEqModel_->XiEq());
}
// solve vegetation model
void modifiedVegetationModel::solve(volVectorField& U, volScalarField& T, volScalarField& w)
{
// solve radiation within vegetation
radiation();
const double p_ = 101325;
// Magnitude of velocity
volScalarField magU("magU", mag(U));
// Bounding velocity
bound(magU, UMin_);
// solve aerodynamic, stomatal resistance
volScalarField new_Tl("new_Tl", Tl_);
// info
Info << " max leaf temp tl=" << max(T.internalField())
<< "k, iteration i=0" << endl;
scalar maxError, maxRelError;
int i;
// solve leaf temperature, iteratively.
int maxIter = 500;
for (i=1; i<=maxIter; i++)
{
// Solve aerodynamc, stomatal resistance
resistance(magU, T, w, new_Tl);
forAll(LAD_, cellI)
{
if (LAD_[cellI] > 10*SMALL)
{
// Initial leaf temperature
if (i==1)
Tl_[cellI];// = T[cellI];//*0. + 300.;//T[cellI];
// Calculate saturated density, specific humidity
rhosat_[cellI] = calc_rhosat(Tl_[cellI]);
evsat_[cellI] = calc_evsat(Tl_[cellI]);
wsat_[cellI] = 0.621945*(evsat_[cellI]/(p_-evsat_[cellI])); // ASHRAE 1, eq.23
// Calculate transpiration rate]);
E_[cellI] = nEvapSides_.value()*LAD_[cellI]*rhoa_.value()*(wsat_[cellI]-w[cellI])/(ra_[cellI]+rs_[cellI]);
//E_[cellI] = 0.0; // No evapotranspiration
// Calculate latent heat flux
Ql_[cellI] = lambda_.value()*E_[cellI];
// Calculate new leaf temperature
new_Tl[cellI] = T[cellI] + (Rn_[cellI] - Ql_[cellI])*(ra_[cellI]/(2.0*rhoa_.value()*cpa_.value()*LAD_[cellI]));
}
}
// info
Info << " max leaf temp tl=" << gMax(new_Tl.internalField())
<< " K, iteration i=" << i << endl;
// Check rel. L-infinity error
maxError = gMax(mag(new_Tl.internalField()-Tl_.internalField()));
maxRelError = maxError/gMax(mag(new_Tl.internalField()));
// update leaf temp.
forAll(Tl_, cellI)
Tl_[cellI] = 0.5*Tl_[cellI]+0.5*new_Tl[cellI];
// convergence check
if (maxRelError < 1e-8)
break;
}
Tl_.correctBoundaryConditions();
// Iteration info
Info << "Vegetation model: Solving for Tl, Final residual = " << maxError
<< ", Final relative residual = " << maxRelError
<< ", No Iterations " << i << endl;
Info << "temperature parameters: max Tl = " << gMax(Tl_)
<< ", min T = " << gMin(T) << ", max T = " << gMax(T) << endl;
Info << "resistances: max rs = " << gMax(rs_)
<< ", max ra = " << gMax(ra_) << endl;
// Final: Solve aerodynamc, stomatal resistance
resistance(magU, T, w, Tl_);
// Final: Update sensible and latent heat flux
forAll(LAD_, cellI)
{
if (LAD_[cellI] > 10*SMALL)
{
// Calculate saturated density, specific humidity
rhosat_[cellI] = calc_rhosat(Tl_[cellI]);
evsat_[cellI] = calc_evsat(Tl_[cellI]);
wsat_[cellI] = 0.621945*(evsat_[cellI]/(p_-evsat_[cellI])); // ASHRAE 1, eq.23
// Calculate transpiration rate
E_[cellI] = nEvapSides_.value()*LAD_[cellI]*rhoa_.value()*(wsat_[cellI]-w[cellI])/(ra_[cellI]+rs_[cellI]); // todo: implement switch for double or single side
// Calculate latent heat flux
Ql_[cellI] = lambda_.value()*E_[cellI];
// Calculate sensible heat flux
Qs_[cellI] = 2.0*rhoa_.value()*cpa_.value()*LAD_[cellI]*(Tl_[cellI]-T[cellI])/ra_[cellI];
}
}
rhosat_.correctBoundaryConditions();
wsat_.correctBoundaryConditions();
E_.correctBoundaryConditions();
Ql_.correctBoundaryConditions();
Qs_.correctBoundaryConditions();
}
