annular_domain.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) 2006-2025 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,
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// LIC// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// LIC// Lesser General Public License for more details.
// LIC//
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// LIC// The authors may be contacted at oomph-lib@maths.man.ac.uk.
// LIC//
// LIC//====================================================================
#ifndef OOMPH_ANNULAR_DOMAIN_HEADER
#define OOMPH_ANNULAR_DOMAIN_HEADER
 
// Generic oomph-lib includes
#include "generic/quadtree.h"
#include "generic/domain.h"
#include "generic/geom_objects.h"
 
namespace oomph
{
  //=================================================================
  /// Annular domain
  //=================================================================
  class AnnularDomain : public Domain
  {
  public:
    /// Constructor: Specify azimuthal fraction (1.0 is 360 degrees)
    /// number of macro elements in azimuthal and radial direction,
    /// inner radius and thickness. Rotate mesh by angle phi.
    AnnularDomain(const double& azimuthal_fraction,
                  const unsigned& ntheta,
                  const unsigned& nr,
                  const double& a,
                  const double& h,
                  const double& phi)
      : Azimuthal_fraction(azimuthal_fraction),
        Inner_radius(a),
        Thickness(h),
        Ntheta(ntheta),
        Nr(nr),
        Phi(phi)
    {
      const unsigned n_macro = ntheta * nr;
      Macro_element_pt.resize(n_macro);
 
      // Create the macro elements
      for (unsigned i = 0; i < n_macro; i++)
      {
        Macro_element_pt[i] = new QMacroElement<2>(this, i);
      }
    }
 
    /// Broken copy constructor
    AnnularDomain(const AnnularDomain&) = delete;
 
    /// Broken assignment operator
    void operator=(const AnnularDomain&) = delete;
 
    /// Destructor: Empty; cleanup done in base class
    ~AnnularDomain() {}
 
 
    /// Vector representation of the  i_macro-th macro element
    /// boundary i_direct (N/S/W/E) at time level t
    /// (t=0: present; t>0: previous):
    /// f(s).
    void macro_element_boundary(const unsigned& t,
                                const unsigned& i_macro,
                                const unsigned& i_direct,
                                const Vector<double>& s,
                                Vector<double>& f);
 
  private:
    /// Azimuthal fraction
    double Azimuthal_fraction;
 
    /// Inner radius
    double Inner_radius;
 
    /// Thickness
    double Thickness;
 
    /// Number of macro elements in azimuthal direction
    unsigned Ntheta;
 
    /// Number of macro elements in radial direction
    unsigned Nr;
 
    /// Rotation angle
    double Phi;
  };
 
 
  /////////////////////////////////////////////////////////////////////////
  /////////////////////////////////////////////////////////////////////////
  /////////////////////////////////////////////////////////////////////////
 
  //=================================================================
  /// Vector representation of the  imacro-th macro element
  /// boundary idirect (N/S/W/E) at time level t
  /// (t=0: present; t>0: previous): f(s)
  //=================================================================
  void AnnularDomain::macro_element_boundary(const unsigned& t,
                                             const unsigned& imacro,
                                             const unsigned& idirect,
                                             const Vector<double>& s,
                                             Vector<double>& f)
  {
    using namespace QuadTreeNames;
 
    // Get coordinates of macro element
    unsigned i_theta = imacro % Ntheta;
    unsigned i_r = (imacro - i_theta) / Ntheta;
 
    // Angle and radius limits
    double theta_lo = Azimuthal_fraction * 2.0 * MathematicalConstants::Pi *
                      double(i_theta) / double(Ntheta);
 
    double theta_hi = Azimuthal_fraction * 2.0 * MathematicalConstants::Pi *
                      double(i_theta + 1) / double(Ntheta);
 
    // Revert direction (convoluted -- don't ask. It mirrors what happens
    // in the mesh...
    theta_lo = -MathematicalConstants::Pi +
               Azimuthal_fraction * 2.0 * MathematicalConstants::Pi - theta_lo;
    theta_hi = -MathematicalConstants::Pi +
               Azimuthal_fraction * 2.0 * MathematicalConstants::Pi - theta_hi;
 
    double r_lo = Inner_radius + Thickness * double(i_r) / double(Nr);
    double r_hi = Inner_radius + Thickness * double(i_r + 1) / double(Nr);
 
    // Actual radius and angle
    double r = 0.0;
    double theta = 0.0;
 
    // Which direction?
    switch (idirect)
    {
      case N:
 
        theta = theta_lo + 0.5 * (s[0] + 1.0) * (theta_hi - theta_lo);
        r = r_hi;
 
        break;
 
      case S:
 
        theta = theta_lo + 0.5 * (s[0] + 1.0) * (theta_hi - theta_lo);
        r = r_lo;
 
        break;
 
      case W:
 
        theta = theta_lo;
        r = r_lo + 0.5 * (s[0] + 1.0) * (r_hi - r_lo);
 
        break;
 
      case E:
 
        theta = theta_hi;
        r = r_lo + 0.5 * (s[0] + 1.0) * (r_hi - r_lo);
 
        break;
 
      default:
        std::ostringstream error_stream;
        error_stream << "idirect is " << idirect << " not one of N, S, W, E"
                     << std::endl;
 
        throw OomphLibError(
          error_stream.str(), OOMPH_CURRENT_FUNCTION, OOMPH_EXCEPTION_LOCATION);
    }
 
    f[0] = r * cos(theta + Phi);
    f[1] = r * sin(theta + Phi);
  }
 
} // namespace oomph
 
#endif