RadiativeHeatFluxBCBase.C

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//* This file is part of the MOOSE framework
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//* https://github.com/idaholab/moose/blob/master/COPYRIGHT
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//* https://www.gnu.org/licenses/lgpl-2.1.html
 
#include "RadiativeHeatFluxBCBase.h"
#include "Function.h"
#include "MathUtils.h"
 
defineLegacyParams(RadiativeHeatFluxBCBase);
 
InputParameters
RadiativeHeatFluxBCBase::validParams()
{
  InputParameters params = IntegratedBC::validParams();
  params.addParam<Real>("stefan_boltzmann_constant", 5.670367e-8, "The Stefan-Boltzmann constant.");
  params.addParam<FunctionName>(
      "Tinfinity", "0", "Temperature of the body in radiative heat transfer.");
  params.addParam<Real>("boundary_emissivity", 1, "Emissivity of the boundary.");
  params.addClassDescription("Boundary condition for radiative heat flux where temperature and the"
                             "temperature of a body in radiative heat transfer are specified.");
  return params;
}
 
RadiativeHeatFluxBCBase::RadiativeHeatFluxBCBase(const InputParameters & parameters)
  : IntegratedBC(parameters),
    _sigma_stefan_boltzmann(getParam<Real>("stefan_boltzmann_constant")),
    _tinf(getFunction("Tinfinity")),
    _eps_boundary(getParam<Real>("boundary_emissivity"))
{
}
 
Real
RadiativeHeatFluxBCBase::computeQpResidual()
{
  Real T4 = MathUtils::pow(_u[_qp], 4);
  Real T4inf = MathUtils::pow(_tinf.value(_t, _q_point[_qp]), 4);
  return _test[_i][_qp] * _sigma_stefan_boltzmann * coefficient() * (T4 - T4inf);
}
 
Real
RadiativeHeatFluxBCBase::computeQpJacobian()
{
  Real T3 = MathUtils::pow(_u[_qp], 3);
  return 4 * _sigma_stefan_boltzmann * _test[_i][_qp] * coefficient() * T3 * _phi[_j][_qp];
}