LevelSetOlssonBubble.C

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//* This file is part of the MOOSE framework
//* https://www.mooseframework.org
//*
//* 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
 
// MOOSE includes
#include "LevelSetOlssonBubble.h"
 
registerMooseObject("LevelSetApp", LevelSetOlssonBubble);
 
template <>
InputParameters
validParams<LevelSetOlssonBubble>()
{
  InputParameters params = validParams<Function>();
  params.addClassDescription("Implementation of 'bubble' ranging from 0 to 1.");
  params.addParam<RealVectorValue>(
      "center", RealVectorValue(0.5, 0.5, 0), "The center of the bubble.");
  params.addParam<Real>("radius", 0.15, "The radius of the bubble.");
  params.addParam<Real>("epsilon", 0.01, "The interface thickness.");
  return params;
}
 
LevelSetOlssonBubble::LevelSetOlssonBubble(const InputParameters & parameters)
  : Function(parameters),
    _center(getParam<RealVectorValue>("center")),
    _radius(getParam<Real>("radius")),
    _epsilon(getParam<Real>("epsilon"))
{
}
 
Real
LevelSetOlssonBubble::value(Real /*t*/, const Point & p) const
{
  const Real x = ((p - _center).norm() - _radius) / _epsilon;
  return 1.0 / (1 + std::exp(x));
}
 
RealGradient
LevelSetOlssonBubble::gradient(Real /*t*/, const Point & p) const
{
  Real norm = (p - _center).norm();
  Real g = (norm - _radius) / _epsilon;
  RealGradient output;
 
  Real g_prime;
  for (unsigned int i = 0; i < LIBMESH_DIM; ++i)
  {
    g_prime = (p(i) - _center(i)) / (_epsilon * norm);
    output(i) = (g_prime * std::exp(g)) / ((std::exp(g) + 1) * (std::exp(g) + 1));
  }
  return output;
}