interface_elements.h

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// LIC// ====================================================================
// LIC// This file forms part of oomph-lib, the object-oriented,
// LIC// multi-physics finite-element library, available
// LIC// at http://www.oomph-lib.org.
// LIC//
// LIC// Copyright (C) 2006-2022 Matthias Heil and Andrew Hazel
// LIC//
// LIC// This library is free software; you can redistribute it and/or
// LIC// modify it under the terms of the GNU Lesser General Public
// LIC// License as published by the Free Software Foundation; either
// LIC// version 2.1 of the License, or (at your option) any later version.
// LIC//
// LIC// This library is distributed in the hope that it will be useful,
// LIC// but WITHOUT ANY WARRANTY; without even the implied warranty of
// LIC// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// LIC// Lesser General Public License for more details.
// LIC//
// LIC// You should have received a copy of the GNU Lesser General Public
// LIC// License along with this library; if not, write to the Free Software
// LIC// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
// LIC// 02110-1301  USA.
// LIC//
// LIC// The authors may be contacted at oomph-lib@maths.man.ac.uk.
// LIC//
// LIC//====================================================================
// Header file for (one-dimensional) free surface elements
// Include guards, to prevent multiple includes
#ifndef OOMPH_INTERFACE_ELEMENTS_HEADER
#define OOMPH_INTERFACE_ELEMENTS_HEADER
 
// Config header generated by autoconfig
#ifdef HAVE_CONFIG_H
#include <oomph-lib-config.h>
#endif
 
#include "../generic/elements.h"
#include "../generic/spines.h"
#include "../generic/shape.h"
#include "../generic/hijacked_elements.h"
 
namespace oomph
{
  //========================================================================
  //=========================================================================
  class FluidInterfaceBoundingElement : public virtual FaceElement
  {
  private:
    typedef void (*WallUnitNormalFctPt)(const Vector<double>& x,
                                        Vector<double>& unit_normal);
 
    WallUnitNormalFctPt Wall_unit_normal_fct_pt;
 
    double* Contact_angle_pt;
 
    double* Ca_pt;
 
  protected:
    unsigned Contact_angle_flag;
 
    Vector<unsigned> U_index_interface_boundary;
 
    virtual int kinematic_local_eqn(const unsigned& n) = 0;
 
    void wall_unit_normal(const Vector<double>& x, Vector<double>& normal)
    {
#ifdef PARANOID
      if (Wall_unit_normal_fct_pt)
      {
#endif
        (*Wall_unit_normal_fct_pt)(x, normal);
#ifdef PARANOID
      }
      else
      {
        throw OomphLibError("Wall unit normal fct has not been set",
                            "FluidInterfaceBoundingElement::wall_unit_normal()",
                            OOMPH_EXCEPTION_LOCATION);
      }
#endif
    }
 
    inline void update_in_external_fd(const unsigned& i)
    {
      // Update the bulk element
      bulk_element_pt()->node_update();
    }
 
    // function to take care of the remesh)
    inline void reset_in_external_fd(const unsigned& i) {}
 
    inline void reset_after_external_fd()
    {
      // Update the bulk element
      bulk_element_pt()->node_update();
    }
 
  public:
    FluidInterfaceBoundingElement()
      : Wall_unit_normal_fct_pt(0),
        Contact_angle_pt(0),
        Ca_pt(0),
        Contact_angle_flag(0)
    {
    }
 
    WallUnitNormalFctPt& wall_unit_normal_fct_pt()
    {
      return Wall_unit_normal_fct_pt;
    }
 
    WallUnitNormalFctPt wall_unit_normal_fct_pt() const
    {
      return Wall_unit_normal_fct_pt;
    }
 
    Vector<unsigned>& u_index_interface_boundary()
    {
      return U_index_interface_boundary;
    }
 
    void set_contact_angle(double* const& angle_pt, const bool& strong = true);
 
    double*& contact_angle_pt()
    {
      return Contact_angle_pt;
    }
 
    double*& ca_pt()
    {
      return Ca_pt;
    }
 
    double ca()
    {
#ifdef PARANOID
      if (Ca_pt != 0)
      {
#endif
        return *Ca_pt;
#ifdef PARANOID
      }
      else
      {
        throw OomphLibError("Capillary number has not been set",
                            "FluidInterfaceBoundingElement::ca()",
                            OOMPH_EXCEPTION_LOCATION);
      }
#endif
    }
 
 
    double& contact_angle()
    {
#ifdef PARANOID
      if (Contact_angle_pt == 0)
      {
        std::string error_message = "Contact angle not set\n";
        error_message +=
          "Please use FluidInterfaceBoundingElement::set_contact_angle()\n";
        throw OomphLibError(
          error_message, OOMPH_CURRENT_FUNCTION, OOMPH_EXCEPTION_LOCATION);
      }
#endif
      return *Contact_angle_pt;
    }
 
    void fill_in_contribution_to_residuals(Vector<double>& residuals)
    {
      // Add the residual contributions using a dummy matrix
      fill_in_generic_residual_contribution_interface_boundary(
        residuals, GeneralisedElement::Dummy_matrix, 0);
    }
 
    virtual void fill_in_generic_residual_contribution_interface_boundary(
      Vector<double>& residuals,
      DenseMatrix<double>& jacobian,
      unsigned flag) = 0;
 
 
    virtual void add_additional_residual_contributions_interface_boundary(
      Vector<double>& residuals,
      DenseMatrix<double>& jacobian,
      const unsigned& flag,
      const Shape& psif,
      const DShape& dpsifds,
      const Vector<double>& interpolated_n,
      const double& W)
    {
    }
 
    void output(std::ostream& outfile)
    {
      FiniteElement::output(outfile);
    }
 
    void output(std::ostream& outfile, const unsigned& n_plot)
    {
      FiniteElement::output(outfile, n_plot);
    }
 
    void output(FILE* file_pt)
    {
      FiniteElement::output(file_pt);
    }
 
    void output(FILE* file_pt, const unsigned& n_plot)
    {
      FiniteElement::output(file_pt, n_plot);
    }
  };
 
 
  //==========================================================================
  //==========================================================================
  class PointFluidInterfaceBoundingElement
    : public FluidInterfaceBoundingElement
  {
  protected:
    void fill_in_generic_residual_contribution_interface_boundary(
      Vector<double>& residuals, DenseMatrix<double>& jacobian, unsigned flag);
 
  public:
    PointFluidInterfaceBoundingElement() : FluidInterfaceBoundingElement() {}
  };
 
 
  //==========================================================================
  //==========================================================================
  class LineFluidInterfaceBoundingElement : public FluidInterfaceBoundingElement
  {
  protected:
    void fill_in_generic_residual_contribution_interface_boundary(
      Vector<double>& residuals, DenseMatrix<double>& jacobian, unsigned flag);
 
  public:
    LineFluidInterfaceBoundingElement() : FluidInterfaceBoundingElement() {}
  };
 
 
  //=======================================================================
  //======================================================================
  class FluidInterfaceElement : public virtual FaceElement
  {
    // Make the bounding element class a friend
    friend class FluidInterfaceBoundingElement;
 
  private:
    double* Ca_pt;
 
    double* St_pt;
 
    static double Default_Physical_Constant_Value;
 
 
  protected:
    Vector<unsigned> U_index_interface;
 
    int External_data_number_of_external_pressure;
 
    Data* Pext_data_pt;
 
    unsigned Index_of_external_pressure_value;
 
    virtual int kinematic_local_eqn(const unsigned& n) = 0;
 
    int pext_local_eqn()
    {
#ifdef PARANOID
      if (External_data_number_of_external_pressure < 0)
      {
        throw OomphLibError("No external pressure has been set\n",
                            OOMPH_CURRENT_FUNCTION,
                            OOMPH_EXCEPTION_LOCATION);
      }
#endif
      return external_local_eqn(External_data_number_of_external_pressure,
                                Index_of_external_pressure_value);
    }
 
    virtual void fill_in_generic_residual_contribution_interface(
      Vector<double>& residuals, DenseMatrix<double>& jacobian, unsigned flag);
 
    virtual double compute_surface_derivatives(
      const Shape& psi,
      const DShape& dpsids,
      const DenseMatrix<double>& interpolated_t,
      const Vector<double>& interpolated_x,
      DShape& dpsidS,
      DShape& dpsidS_div) = 0;
 
    virtual void add_additional_residual_contributions_interface(
      Vector<double>& residuals,
      DenseMatrix<double>& jacobian,
      const unsigned& flag,
      const Shape& psif,
      const DShape& dpsifds,
      const DShape& dpsifdS,
      const DShape& dpsifdS_div,
      const Vector<double>& s,
      const Vector<double>& interpolated_x,
      const Vector<double>& interpolated_n,
      const double& W,
      const double& J)
    {
    }
 
  public:
    FluidInterfaceElement() : Pext_data_pt(0)
    {
      // Initialise pointer to capillary number
      Ca_pt = 0;
 
      // Set the Strouhal number to the default value
      St_pt = &Default_Physical_Constant_Value;
    }
 
    virtual double sigma(const Vector<double>& s_local)
    {
      return 1.0;
    }
 
    void fill_in_contribution_to_residuals(Vector<double>& residuals)
    {
      // Add the residual contributions
      fill_in_generic_residual_contribution_interface(
        residuals, GeneralisedElement::Dummy_matrix, 0);
    }
 
 
    const double& ca() const
    {
#ifdef PARANOID
      if (Ca_pt != 0)
      {
#endif
        return *Ca_pt;
#ifdef PARANOID
      }
      else
      {
        throw OomphLibError("Capillary number has not been set",
                            "FluidInterfaceElement::ca()",
                            OOMPH_EXCEPTION_LOCATION);
      }
#endif
    }
 
    double*& ca_pt()
    {
      return Ca_pt;
    }
 
    const double& st() const
    {
      return *St_pt;
    }
 
    double*& st_pt()
    {
      return St_pt;
    }
 
    double u(const unsigned& j, const unsigned& i)
    {
      return node_pt(j)->value(U_index_interface[i]);
    }
 
    double interpolated_u(const Vector<double>& s, const unsigned& i);
 
    double pext() const
    {
      // If the external pressure has not been set, then return a
      // default value of zero.
      if (Pext_data_pt == 0)
      {
        return 0.0;
      }
      // Otherwise return the appropriate value
      else
      {
        return Pext_data_pt->value(Index_of_external_pressure_value);
      }
    }
 
    void set_external_pressure_data(Data* external_pressure_data_pt)
    {
#ifdef PARANOID
      if (external_pressure_data_pt->nvalue() != 1)
      {
        std::ostringstream error_message;
        error_message
          << "External pressure Data must only contain a single value!\n"
          << "This one contains " << external_pressure_data_pt->nvalue()
          << std::endl;
 
        throw OomphLibError(error_message.str(),
                            OOMPH_CURRENT_FUNCTION,
                            OOMPH_EXCEPTION_LOCATION);
      }
#endif
 
      // Store pointer explicitly
      Pext_data_pt = external_pressure_data_pt;
 
      // Add the external pressure to the element's external Data?
      // But do not finite-difference with respect to it
      this->add_external_data(Pext_data_pt, false);
 
      // The external pressure has just been promoted to become
      // external Data of this element -- what is its number?
      External_data_number_of_external_pressure = this->nexternal_data() - 1;
 
      // Index of pressure value in Data object
      Index_of_external_pressure_value = 0;
    }
 
    void set_external_pressure_data(
      Data* external_pressure_data_pt,
      const unsigned& index_of_external_pressure_value)
    {
      // Index of pressure value in Data object
      Index_of_external_pressure_value = index_of_external_pressure_value;
 
#ifdef PARANOID
      if (index_of_external_pressure_value >=
          external_pressure_data_pt->nvalue())
      {
        std::ostringstream error_message;
        error_message << "External pressure Data only contains "
                      << external_pressure_data_pt->nvalue() << " values\n"
                      << "You have declared value "
                      << index_of_external_pressure_value
                      << " to be the value representing the pressure\n"
                      << std::endl;
        throw OomphLibError(error_message.str(),
                            OOMPH_CURRENT_FUNCTION,
                            OOMPH_EXCEPTION_LOCATION);
      }
#endif
 
      // Store pointer explicitly
      Pext_data_pt = external_pressure_data_pt;
 
      // Add the external pressure to the element's external Data?
      // But do not finite-difference with respect to it
      this->add_external_data(Pext_data_pt, false);
 
      // The external pressure has just been promoted to become
      // external Data of this element -- what is its number?
      External_data_number_of_external_pressure = this->nexternal_data() - 1;
    }
 
 
    virtual FluidInterfaceBoundingElement* make_bounding_element(
      const int& face_index)
    {
      throw OomphLibError("Virtual function not yet implemented",
                          OOMPH_CURRENT_FUNCTION,
                          OOMPH_EXCEPTION_LOCATION);
      return 0;
    }
 
 
    virtual void hijack_kinematic_conditions(
      const Vector<unsigned>& bulk_node_number) = 0;
 
    void output(std::ostream& outfile)
    {
      FiniteElement::output(outfile);
    }
 
    void output(std::ostream& outfile, const unsigned& n_plot);
 
    void output(FILE* file_pt)
    {
      FiniteElement::output(file_pt);
    }
 
    void output(FILE* file_pt, const unsigned& n_plot);
  };
 
 
  //=============================================================
  //=============================================================
  class LineDerivatives
  {
  public:
    // Empty Constructor
    LineDerivatives() {}
 
  protected:
    double compute_surface_derivatives(
      const Shape& psi,
      const DShape& dpsids,
      const DenseMatrix<double>& interpolated_t,
      const Vector<double>& interpolated_x,
      DShape& surface_gradient,
      DShape& surface_divergence);
  };
 
 
  //=============================================================
  //=============================================================
  class AxisymmetricDerivatives
  {
  public:
    // Empty Constructor
    AxisymmetricDerivatives() {}
 
  protected:
    double compute_surface_derivatives(
      const Shape& psi,
      const DShape& dpsids,
      const DenseMatrix<double>& interpolated_t,
      const Vector<double>& interpolated_x,
      DShape& surface_gradient,
      DShape& surface_divergence);
  };
 
 
  //=============================================================
  //=============================================================
  class SurfaceDerivatives
  {
  public:
    // Empty Constructor
    SurfaceDerivatives() {}
 
  protected:
    double compute_surface_derivatives(
      const Shape& psi,
      const DShape& dpsids,
      const DenseMatrix<double>& interpolated_t,
      const Vector<double>& interpolated_x,
      DShape& surface_gradient,
      DShape& surface_divergence);
  };
 
 
} // namespace oomph
 
#endif