Compute the gradient interface terms for a multiphase system. More...

#include <ACMultiInterface.h>

Inheritance diagram for ACMultiInterface:

Public Member Functions
	ACMultiInterface (const InputParameters &parameters)

Protected Member Functions
virtual Real	computeQpResidual ()

virtual Real	computeQpJacobian ()

virtual Real	computeQpOffDiagJacobian (unsigned int)

Protected Attributes
unsigned int	_num_etas
	Order parameters. More...

std::vector< const VariableValue * >	_eta

std::vector< const VariableGradient * >	_grad_eta

std::vector< int >	_eta_vars
	Lookup table from couple variable number into the etas vector. More...

unsigned int	_a
	Index of the eta this kernel is operating on. More...

std::vector< MaterialPropertyName >	_kappa_names
	Interface gradient prefactor. More...

std::vector< const MaterialProperty< Real > * >	_kappa

const MaterialProperty< Real > &	_L
	Mobility. More...

Detailed Description

Compute the gradient interface terms for a multiphase system.

This includes cross terms of the form \( \left( \eta_a\nabla\eta_b - \eta_b\nabla\eta_a \right)^2\). Note that in a two phase system with \( \eta = \eta_b = 1-\eta_a \) the regular ACInterface kernel can be used as the gradient interface term simplifies to the usual \( ()\nabla\eta)^2 \) form.

http://mooseframework.org/wiki/PhysicsModules/PhaseField/DevelopingModels/MultiPhaseModels/ACMultiInterface/

Definition at line 29 of file ACMultiInterface.h.

Constructor & Destructor Documentation

◆ ACMultiInterface()

ACMultiInterface::ACMultiInterface ( const InputParameters & parameters )

Definition at line 31 of file ACMultiInterface.C.

   : Kernel(parameters),
     _num_etas(coupledComponents("etas")),
     _eta(_num_etas),
     _grad_eta(_num_etas),
     _eta_vars(_fe_problem.getNonlinearSystemBase().nVariables(), -1),
     _kappa_names(getParam<std::vector<MaterialPropertyName>>("kappa_names")),
     _kappa(_num_etas),
     _L(getMaterialProperty<Real>("mob_name"))
 {
   if (_num_etas != _kappa_names.size())
     paramError("kappa_names", "Supply the same number of etas and kappa_names.");
  
   unsigned int nvariables = _fe_problem.getNonlinearSystemBase().nVariables();
  
   int a = -1;
   for (unsigned int i = 0; i < _num_etas; ++i)
   {
     // get all order parameters and their gradients
     _eta[i] = &coupledValue("etas", i);
     _grad_eta[i] = &coupledGradient("etas", i);
  
     // populate lookup table form jvar to _eta index
     unsigned int var = coupled("etas", i);
     if (var < nvariables)
       _eta_vars[var] = i;
  
     // get the index of the variable the kernel is operating on
     if (coupled("etas", i) == _var.number())
       a = i;
  
     // get gradient prefactors
     _kappa[i] = &getMaterialPropertyByName<Real>(_kappa_names[i]);
   }
  
   if (a < 0)
     paramError(
         "etas", "Kernel variable must be listed in etas for ACMultiInterface kernel ", name());
   else
     _a = a;
 }

Member Function Documentation

◆ computeQpJacobian()

Real ACMultiInterface::computeQpJacobian ( )

protectedvirtual

Definition at line 106 of file ACMultiInterface.C.

 {
   Real sum = 0.0;
   for (unsigned int b = 0; b < _num_etas; ++b)
   {
     // skip the diagonal term (does not contribute)
     if (b == _a)
       continue;
  
     sum += (*_kappa[b])[_qp] *
            (2.0 * _test[_i][_qp] *
                 ((_phi[_j][_qp] * (*_grad_eta[b])[_qp] - (*_eta[b])[_qp] * _grad_phi[_j][_qp]) *
                  (*_grad_eta[b])[_qp]) +
             (-(_phi[_j][_qp] * (*_eta[b])[_qp] * _grad_test[_i][_qp] +
                _test[_i][_qp] * (*_eta[b])[_qp] * _grad_phi[_j][_qp] +
                _test[_i][_qp] * _phi[_j][_qp] * (*_grad_eta[b])[_qp]) *
              (*_grad_eta[b])[_qp]) -
             (-((*_eta[b])[_qp] * (*_eta[b])[_qp] * _grad_test[_i][_qp] +
                2.0 * _test[_i][_qp] * (*_eta[b])[_qp] * (*_grad_eta[b])[_qp]) *
              _grad_phi[_j][_qp]));
   }
  
   return _L[_qp] * sum;
 }

◆ computeQpOffDiagJacobian()

Real ACMultiInterface::computeQpOffDiagJacobian ( unsigned int jvar )

protectedvirtual

Definition at line 132 of file ACMultiInterface.C.

 {
   const VariableValue & _eta_a = _u;
   const VariableGradient & _grad_eta_a = _grad_u;
  
   const int b = _eta_vars[jvar];
   if (b < 0)
     return 0.0;
  
   return _L[_qp] * (*_kappa[b])[_qp] *
          (2.0 * _test[_i][_qp] *
               ((_eta_a[_qp] * _grad_phi[_j][_qp] - _phi[_j][_qp] * _grad_eta_a[_qp]) *
                    (*_grad_eta[b])[_qp] +
                (_eta_a[_qp] * (*_grad_eta[b])[_qp] - (*_eta[b])[_qp] * _grad_eta_a[_qp]) *
                    _grad_phi[_j][_qp]) +
           (-(_eta_a[_qp] * _phi[_j][_qp] * _grad_test[_i][_qp] +
              _test[_i][_qp] * _phi[_j][_qp] * _grad_eta_a[_qp] +
              _test[_i][_qp] * _eta_a[_qp] * _grad_phi[_j][_qp]) *
                (*_grad_eta[b])[_qp] -
            (_eta_a[_qp] * (*_eta[b])[_qp] * _grad_test[_i][_qp] +
             _test[_i][_qp] * (*_eta[b])[_qp] * _grad_eta_a[_qp] +
             _test[_i][_qp] * _eta_a[_qp] * (*_grad_eta[b])[_qp]) *
                _grad_phi[_j][_qp]) -
           (-(2.0 * (*_eta[b])[_qp] * _phi[_j][_qp] * _grad_test[_i][_qp] +
              2.0 * _test[_i][_qp] *
                  (_phi[_j][_qp] * (*_grad_eta[b])[_qp] + (*_eta[b])[_qp] * _grad_phi[_j][_qp])) *
            _grad_eta_a[_qp]));
 }

◆ computeQpResidual()

Real ACMultiInterface::computeQpResidual ( )

protectedvirtual

Definition at line 74 of file ACMultiInterface.C.

 {
   const VariableValue & _eta_a = _u;
   const VariableGradient & _grad_eta_a = _grad_u;
  
   Real sum = 0.0;
   for (unsigned int b = 0; b < _num_etas; ++b)
   {
     // skip the diagonal term (does not contribute)
     if (b == _a)
       continue;
  
     sum += (*_kappa[b])[_qp] *
            (
                // order 1 terms
                2.0 * _test[_i][_qp] *
                    (_eta_a[_qp] * (*_grad_eta[b])[_qp] - (*_eta[b])[_qp] * _grad_eta_a[_qp]) *
                    (*_grad_eta[b])[_qp]
                // volume terms
                + (-(_eta_a[_qp] * (*_eta[b])[_qp] * _grad_test[_i][_qp] +
                     _test[_i][_qp] * (*_eta[b])[_qp] * _grad_eta_a[_qp] +
                     _test[_i][_qp] * _eta_a[_qp] * (*_grad_eta[b])[_qp]) *
                   (*_grad_eta[b])[_qp]) -
                (-((*_eta[b])[_qp] * (*_eta[b])[_qp] * _grad_test[_i][_qp] +
                   2.0 * _test[_i][_qp] * (*_eta[b])[_qp] * (*_grad_eta[b])[_qp]) *
                 _grad_eta_a[_qp]));
   }
  
   return _L[_qp] * sum;
 }