CoupledForceNodalKernel.C

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//* This file is part of the MOOSE framework
//* https://mooseframework.inl.gov
//*
//* All rights reserved, see COPYRIGHT for full restrictions
//* https://github.com/idaholab/moose/blob/master/COPYRIGHT
//*
//* Licensed under LGPL 2.1, please see LICENSE for details
//* https://www.gnu.org/licenses/lgpl-2.1.html

#include "CoupledForceNodalKernel.h"

registerMooseObject("MooseApp", CoupledForceNodalKernel);

InputParameters
CoupledForceNodalKernel::validParams()
{
  InputParameters params = NodalKernel::validParams();
  params.addClassDescription("Adds a force proportional to the value of the coupled variable");
  params.addRequiredCoupledVar("v", "The coupled variable which provides the force");
  params.addParam<Real>(
      "coef", 1.0, "Coefficent ($\\sigma$) multiplier for the coupled force term.");

  return params;
}

CoupledForceNodalKernel::CoupledForceNodalKernel(const InputParameters & parameters)
  : NodalKernel(parameters),
    _v_var(coupled("v")),
    _v(coupledValue("v")),
    _coef(getParam<Real>("coef"))
{
  if (_var.number() == _v_var)
    mooseError(
        "Coupled variable 'v' needs to be different from 'variable' with CoupledForceNodalKernel, "
        "consider using Reaction or somethig similar");
}

Real
CoupledForceNodalKernel::computeQpResidual()
{
  return -_coef * _v[_qp];
}

Real
CoupledForceNodalKernel::computeQpJacobian()
{
  return 0;
}

Real
CoupledForceNodalKernel::computeQpOffDiagJacobian(unsigned int jvar)
{
  if (jvar == _v_var)
    return -_coef;
  return 0.0;
}