rhs_operator.h

/*  ______________________________________________________________________
 *
 *  ExaDG - High-Order Discontinuous Galerkin for the Exa-Scale
 *
 *  Copyright (C) 2021 by the ExaDG authors
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program. If not, see <https://www.gnu.org/licenses/>.
 *  ______________________________________________________________________
 */
 
#ifndef EXADG_INCOMPRESSIBLE_NAVIER_STOKES_SPATIAL_DISCRETIZATION_OPERATORS_RHS_OPERATOR_H_
#define EXADG_INCOMPRESSIBLE_NAVIER_STOKES_SPATIAL_DISCRETIZATION_OPERATORS_RHS_OPERATOR_H_
 
// ExaDG
#include <exadg/functions_and_boundary_conditions/evaluate_functions.h>
#include <exadg/matrix_free/integrators.h>
#include <exadg/operators/mapping_flags.h>
 
namespace ExaDG
{
namespace IncNS
{
namespace Operators
{
template<int dim>
struct RHSKernelData
{
  RHSKernelData()
    : boussinesq_term(false),
      boussinesq_dynamic_part_only(false),
      thermal_expansion_coefficient(1.0),
      reference_temperature(0.0)
  {
  }
 
  std::shared_ptr<dealii::Function<dim>> f;
 
  // Boussinesq term
  bool                                   boussinesq_term;
  bool                                   boussinesq_dynamic_part_only;
  double                                 thermal_expansion_coefficient;
  double                                 reference_temperature;
  std::shared_ptr<dealii::Function<dim>> gravitational_force;
};
 
template<int dim, typename Number>
class RHSKernel
{
private:
  typedef dealii::VectorizedArray<Number>                         scalar;
  typedef dealii::Tensor<1, dim, dealii::VectorizedArray<Number>> vector;
 
  typedef CellIntegrator<dim, dim, Number> Integrator;
  typedef CellIntegrator<dim, 1, Number>   IntegratorScalar;
 
public:
  void
  reinit(RHSKernelData<dim> const & data_in) const
  {
    data = data_in;
  }
 
  static MappingFlags
  get_mapping_flags()
  {
    MappingFlags flags;
 
    flags.cells = dealii::update_JxW_values |
                  dealii::update_quadrature_points; // q-points due to rhs function f
 
    // no face integrals
 
    return flags;
  }
 
  /*
   * Volume flux, i.e., the term occurring in the volume integral
   */
  inline DEAL_II_ALWAYS_INLINE //
    vector
    get_volume_flux(Integrator const &       integrator,
                    IntegratorScalar const & integrator_temperature,
                    unsigned int const       q,
                    Number const &           time) const
  {
    dealii::Point<dim, scalar> q_points = integrator.quadrature_point(q);
 
    vector f = FunctionEvaluator<1, dim, Number>::value(*(data.f), q_points, time);
 
    if(data.boussinesq_term)
    {
      vector g =
        FunctionEvaluator<1, dim, Number>::value(*(data.gravitational_force), q_points, time);
      scalar T     = integrator_temperature.get_value(q);
      scalar T_ref = data.reference_temperature;
      // solve only for the dynamic pressure variations
      if(data.boussinesq_dynamic_part_only)
        f += g * (-data.thermal_expansion_coefficient * (T - T_ref));
      else // includes hydrostatic component
        f += g * (1.0 - data.thermal_expansion_coefficient * (T - T_ref));
    }
 
    return f;
  }
 
private:
  mutable RHSKernelData<dim> data;
};
 
} // namespace Operators
 
 
template<int dim>
struct RHSOperatorData
{
  RHSOperatorData() : dof_index(0), quad_index(0), dof_index_scalar(2)
  {
  }
 
  unsigned int dof_index;
  unsigned int quad_index;
 
  unsigned int dof_index_scalar;
 
  Operators::RHSKernelData<dim> kernel_data;
};
 
template<int dim, typename Number>
class RHSOperator
{
public:
  typedef RHSOperator<dim, Number> This;
 
  typedef dealii::LinearAlgebra::distributed::Vector<Number> VectorType;
 
  typedef std::pair<unsigned int, unsigned int> Range;
 
  typedef CellIntegrator<dim, dim, Number> Integrator;
 
  typedef CellIntegrator<dim, 1, Number> IntegratorScalar;
 
  RHSOperator();
 
  void
  initialize(dealii::MatrixFree<dim, Number> const & matrix_free,
             RHSOperatorData<dim> const &            data);
 
  void
  evaluate(VectorType & dst, Number const evaluation_time) const;
 
  void
  evaluate_add(VectorType & dst, Number const evaluation_time) const;
 
  void
  set_temperature(VectorType const & T);
 
private:
  void
  do_cell_integral(Integrator & integrator, IntegratorScalar & integrator_temperature) const;
 
  void
  cell_loop(dealii::MatrixFree<dim, Number> const & matrix_free,
            VectorType &                            dst,
            VectorType const &                      src,
            Range const &                           cell_range) const;
 
  dealii::MatrixFree<dim, Number> const * matrix_free;
 
  RHSOperatorData<dim> data;
 
  mutable double time;
 
  Operators::RHSKernel<dim, Number> kernel;
 
  VectorType const * temperature;
};
 
} // namespace IncNS
} // namespace ExaDG
 
#endif /* EXADG_INCOMPRESSIBLE_NAVIER_STOKES_SPATIAL_DISCRETIZATION_OPERATORS_RHS_OPERATOR_H_ \
        */