KKSPhaseChemicalPotential Class Reference

Enforce the equality of the chemical potentials in the two phases. More...

#include <KKSPhaseChemicalPotential.h>

Inheritance diagram for KKSPhaseChemicalPotential:

Public Member Functions
	KKSPhaseChemicalPotential (const InputParameters &parameters)

Protected Member Functions
virtual Real	computeQpResidual ()
virtual Real	computeQpJacobian ()
virtual Real	computeQpOffDiagJacobian (unsigned int jvar)
virtual void	initialSetup ()

Private Attributes
unsigned int	_cb_var
	coupled variable for cb More...
VariableName	_cb_name
const MaterialProperty< Real > &	_dfadca
	material properties we need to access More...
const MaterialProperty< Real > &	_dfbdcb
const MaterialProperty< Real > &	_d2fadca2
const MaterialProperty< Real > &	_d2fbdcbca
std::vector< const MaterialProperty< Real > * >	_d2fadcadarg
std::vector< const MaterialProperty< Real > * >	_d2fbdcbdarg
const Real	_ka
	site fractions More...
const Real	_kb

Detailed Description

Enforce the equality of the chemical potentials in the two phases.

Eq. (21) in the original KKS paper.

\( dF_a/dc_a = dF_b/dc_b \)

We need to supply two free energy functions (i.e. KKSBaseMaterial) by giving two "base names" ('Fa', 'Fb'). We supply concentration \( c_a \) as the non-linear variable and \( c_b \) as a coupled variable (compare this to KKSPhaseConcentration, where the non-linear variable is the other phase concentration \( c_b \)!)

See also

KKSPhaseConcentration

Definition at line 36 of file KKSPhaseChemicalPotential.h.

Constructor & Destructor Documentation

KKSPhaseChemicalPotential()

KKSPhaseChemicalPotential::KKSPhaseChemicalPotential

(

const InputParameters &

parameters

)

Definition at line 52 of file KKSPhaseChemicalPotential.C.

  : DerivativeMaterialInterface<JvarMapKernelInterface<Kernel>>(parameters),
    _cb_var(coupled("cb")),
    _cb_name(getVar("cb", 0)->name()),
    // first derivatives
    _dfadca(getMaterialPropertyDerivative<Real>("fa_name", _var.name())),
    _dfbdcb(getMaterialPropertyDerivative<Real>("fb_name", _cb_name)),
    // second derivatives d2F/dx*dca for jacobian diagonal elements
    _d2fadca2(getMaterialPropertyDerivative<Real>("fa_name", _var.name(), _var.name())),
    _d2fbdcbca(getMaterialPropertyDerivative<Real>("fb_name", _cb_name, _var.name())),
    // site fractions
    _ka(getParam<Real>("ka")),
    _kb(getParam<Real>("kb"))
{
  MooseVariableFEBase * arg;
  unsigned int i;
 
#ifdef DEBUG
  _console << "KKSPhaseChemicalPotential(" << name() << ") " << _var.name() << ' ' << _cb_name
           << '\n';
#endif
 
  unsigned int nvar = _coupled_moose_vars.size();
  _d2fadcadarg.resize(nvar);
  _d2fbdcbdarg.resize(nvar);
 
  for (i = 0; i < nvar; ++i)
  {
    // get the moose variable
    arg = _coupled_moose_vars[i];
 
    // lookup table for the material properties representing the derivatives needed for the
    // off-diagonal jacobian
    _d2fadcadarg[i] = &getMaterialPropertyDerivative<Real>("fa_name", _var.name(), arg->name());
    _d2fbdcbdarg[i] = &getMaterialPropertyDerivative<Real>("fb_name", _cb_name, arg->name());
  }
}

Member Function Documentation

computeQpJacobian()

Real KKSPhaseChemicalPotential::computeQpJacobian ( )

protectedvirtual

Definition at line 105 of file KKSPhaseChemicalPotential.C.

{
  // for on diagonal we return the d/dca derivative of the residual
  return _test[_i][_qp] * _phi[_j][_qp] * (_d2fadca2[_qp] / _ka - _d2fbdcbca[_qp] / _kb);
}

computeQpOffDiagJacobian()

Real KKSPhaseChemicalPotential::computeQpOffDiagJacobian ( unsigned int  jvar )

protectedvirtual

Definition at line 112 of file KKSPhaseChemicalPotential.C.

{
  // get the coupled variable jvar is referring to
  const unsigned int cvar = mapJvarToCvar(jvar);
 
  return _test[_i][_qp] * _phi[_j][_qp] *
         ((*_d2fadcadarg[cvar])[_qp] / _ka - (*_d2fbdcbdarg[cvar])[_qp] / _kb);
}

computeQpResidual()

Real KKSPhaseChemicalPotential::computeQpResidual ( )

protectedvirtual

Definition at line 98 of file KKSPhaseChemicalPotential.C.

{
  // enforce _dfadca==_dfbdcb
  return _test[_i][_qp] * (_dfadca[_qp] / _ka - _dfbdcb[_qp] / _kb);
}

initialSetup()

void KKSPhaseChemicalPotential::initialSetup ( )

protectedvirtual

Definition at line 91 of file KKSPhaseChemicalPotential.C.

{
  validateNonlinearCoupling<Real>("fa_name");
  validateNonlinearCoupling<Real>("fb_name");
}

Member Data Documentation

_cb_name

VariableName KKSPhaseChemicalPotential::_cb_name

private

Definition at line 50 of file KKSPhaseChemicalPotential.h.

Referenced by KKSPhaseChemicalPotential().

_cb_var

unsigned int KKSPhaseChemicalPotential::_cb_var

private

coupled variable for cb

Definition at line 49 of file KKSPhaseChemicalPotential.h.

_d2fadca2

const MaterialProperty<Real>& KKSPhaseChemicalPotential::_d2fadca2

private

Definition at line 55 of file KKSPhaseChemicalPotential.h.

Referenced by computeQpJacobian().

_d2fadcadarg

std::vector<const MaterialProperty<Real> *> KKSPhaseChemicalPotential::_d2fadcadarg

private

Definition at line 58 of file KKSPhaseChemicalPotential.h.

Referenced by computeQpOffDiagJacobian(), and KKSPhaseChemicalPotential().

_d2fbdcbca

const MaterialProperty<Real>& KKSPhaseChemicalPotential::_d2fbdcbca

private

Definition at line 56 of file KKSPhaseChemicalPotential.h.

Referenced by computeQpJacobian().

_d2fbdcbdarg

std::vector<const MaterialProperty<Real> *> KKSPhaseChemicalPotential::_d2fbdcbdarg

private

Definition at line 59 of file KKSPhaseChemicalPotential.h.

Referenced by computeQpOffDiagJacobian(), and KKSPhaseChemicalPotential().

_dfadca

const MaterialProperty<Real>& KKSPhaseChemicalPotential::_dfadca

private

material properties we need to access

Definition at line 53 of file KKSPhaseChemicalPotential.h.

Referenced by computeQpResidual().

_dfbdcb

const MaterialProperty<Real>& KKSPhaseChemicalPotential::_dfbdcb

private

Definition at line 54 of file KKSPhaseChemicalPotential.h.

Referenced by computeQpResidual().

_ka

const Real KKSPhaseChemicalPotential::_ka

private

site fractions

Definition at line 62 of file KKSPhaseChemicalPotential.h.

Referenced by computeQpJacobian(), computeQpOffDiagJacobian(), and computeQpResidual().

_kb

const Real KKSPhaseChemicalPotential::_kb

private

Definition at line 63 of file KKSPhaseChemicalPotential.h.

Referenced by computeQpJacobian(), computeQpOffDiagJacobian(), and computeQpResidual().

---

The documentation for this class was generated from the following files:

• phase_field/include/kernels/KKSPhaseChemicalPotential.h
• phase_field/src/kernels/KKSPhaseChemicalPotential.C