fsi_driven_cavity_mesh.template.cc

Go to the documentation of this file.

//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//    Version 1.0; svn revision $LastChangedRevision$
//LIC//
//LIC// $LastChangedDate$
//LIC// 
//LIC// Copyright (C) 2006-2016 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//====================================================================
#ifndef OOMPH_FSI_DRIVEN_CAVITY_MESH_TEMPLATE_CC
#define OOMPH_FSI_DRIVEN_CAVITY_MESH_TEMPLATE_CC

//Include the headers file for collapsible channel
#include "fsi_driven_cavity_mesh.template.h"


namespace oomph
{

//========================================================================
/// Constructor: Pass number of elements, lengths, pointer to GeomObject
/// that defines the collapsible segment and pointer to TimeStepper
/// (defaults to the default timestepper, Steady). 
//========================================================================
template <class ELEMENT>
FSIDrivenCavityMesh<ELEMENT>::FSIDrivenCavityMesh(
 const unsigned& nx, 
 const unsigned& ny, 
 const double& lx, 
 const double& ly,
 const double& gap_fraction,
 GeomObject* wall_pt,
 TimeStepper* time_stepper_pt)
 : SimpleRectangularQuadMesh<ELEMENT>(nx,ny,lx,ly,time_stepper_pt),
   Nx(nx), Ny(ny), Gap_fraction(gap_fraction), Wall_pt(wall_pt)
{
 // Mesh can only be built with 2D Qelements.
 MeshChecker::assert_geometric_element<QElementGeometricBase,ELEMENT>(2);
 
 // Update the boundary numbering scheme and set boundary coordinate 
 //-----------------------------------------------------------------
 
 // (Note: The original SimpleRectangularQuadMesh had four boundaries.
 // We need to overwrite the boundary lookup scheme for the current
 // mesh so that the collapsible segment becomes identifiable).
 // While we're doing this, we're also setting up a boundary 
 // coordinate for the nodes located on the collapsible segment.
 // The boundary coordinate can be used to setup FSI.

 // How many boundaries does the mesh have now?
 unsigned nbound=this->nboundary();
 for (unsigned b=0;b<nbound;b++)
  {
   // Remove all nodes on this boundary from the mesh's lookup scheme
   // and also delete the reverse lookup scheme held by the nodes
   this->remove_boundary_nodes(b);
  }
 
#ifdef PARANOID
 // Sanity check
 unsigned nnod=this->nnode();
 for (unsigned j=0;j<nnod;j++)
  {
   if (this->node_pt(j)->is_on_boundary())
    {
     std::ostringstream error_message;
     error_message << "Node " << j << "is still on boundary " << std::endl;
     
     throw OomphLibError(error_message.str(),
                         OOMPH_CURRENT_FUNCTION,
                         OOMPH_EXCEPTION_LOCATION);
    }
  }
#endif
 
 //Change the numbers of boundaries
 this->set_nboundary(6);
 
 // Get the number of nodes along the element edge from first element
 unsigned nnode_1d=this->finite_element_pt(0)->nnode_1d();
 
 // Vector of Lagrangian coordinates used as boundary coordinate
 Vector<double> zeta(1);
  
 // Zeta increment over elements (used for assignment of
 // boundary coordinate)
 double dzeta= lx/double(nx);
 
 // Manually loop over the elements near the boundaries and
 // assign nodes to boundaries. Also set up boundary coordinate
 unsigned nelem=this->nelement();
 for (unsigned e=0;e<nelem;e++)
  {
   // Bottom row of elements
   if (e<nx)
    {
     for (unsigned i=0;i<nnode_1d;i++)
      {
       this->add_boundary_node(0, this->finite_element_pt(e)->node_pt(i));
      }
    }
   // Collapsible bit
   if (e>((ny-1)*nx)-1)
    {
     for (unsigned i=0;i<nnode_1d;i++)
      {
       this->add_boundary_node(3,
                               this->finite_element_pt(e)->node_pt(2*nnode_1d+i));
       
       // What column of elements are we in?
       unsigned ix=e-(ny-1)*nx;
       
        // Zeta coordinate
        zeta[0]=double(ix)*dzeta+double(i)*dzeta/double(nnode_1d-1);
       
       // Set boundary coordinate
       this->finite_element_pt(e)->node_pt(2*nnode_1d+i)->
        set_coordinates_on_boundary(3,zeta);
      }
    }
   // Left end
   if (e%(nx)==0)
    {
     for (unsigned i=0;i<nnode_1d;i++)
      {
       Node* nod_pt=this->finite_element_pt(e)->node_pt(i*nnode_1d);

       // Rigid bit?
       if (nod_pt->x(1)>=ly*Gap_fraction)
        {
         this->add_boundary_node(4,nod_pt);
        }
       // Free bit
       else
        {
         this->add_boundary_node(5,nod_pt);
        }
      }
    }
   // Right end
   if (e%nx==nx-1)
    {
     for (unsigned i=0;i<nnode_1d;i++)
      {
       Node* nod_pt=this->finite_element_pt(e)->node_pt((i+1)*nnode_1d-1);

       // Rigid bit?
       if (nod_pt->x(1)>=ly*Gap_fraction)
        {
         this->add_boundary_node(2,nod_pt);
        }
       // Free bit
       else
        {
         this->add_boundary_node(1,nod_pt);
        }
      }
    }
  }
 
 // Re-setup lookup scheme that establishes which elements are located
 // on the mesh boundaries (doesn't need to be wiped)
 this->setup_boundary_element_info();
 
 //We have only bothered to parametrise boundary 3
 this->Boundary_coordinate_exists[3] = true;   
}




///////////////////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////////////////



//=================================================================
/// Perform algebraic mesh update at time level t (t=0: present; 
/// t>0: previous)
//=================================================================
template<class ELEMENT>
void AlgebraicFSIDrivenCavityMesh<ELEMENT>::algebraic_node_update(
 const unsigned& t, AlgebraicNode*& node_pt)
{


#ifdef PARANOID
 // We're updating the nodal positions (!) at time level t
 // and determine them by evaluating the wall GeomObject's
 // position at that gime level. I believe this only makes sense
 // if the t-th history value in the positional timestepper
 // actually represents previous values (rather than some
 // generalised quantity). Hence if this function is called with 
 // t>nprev_values(), we issue a warning and terminate the execution. 
 // It *might* be possible that the code still works correctly
 // even if this condition is violated (e.g. if the GeomObject's 
 // position() function returns the appropriate "generalised"
 // position value that is required by the timestepping scheme but it's 
 // probably worth flagging this up and forcing the user to manually switch
 // off this warning if he/she is 100% sure that this is kosher.
 if (t>node_pt->position_time_stepper_pt()->nprev_values())
  {
   std::string error_message =
    "Trying to update the nodal position at a time level";
   error_message += "beyond the number of previous values in the nodes'";
   error_message += "position timestepper. This seems highly suspect!";
   error_message += "If you're sure the code behaves correctly";
   error_message += "in your application, remove this warning ";
   error_message += "or recompile with PARNOID switched off.";

   std::string function_name =
    "AlgebraicFSIDrivenCavityMesh::";
   function_name += "algebraic_node_update()";

   throw OomphLibError(error_message,
                       OOMPH_CURRENT_FUNCTION,
                       OOMPH_EXCEPTION_LOCATION);
  }
#endif

 // Extract references for update by copy construction
 Vector<double> ref_value(node_pt->vector_ref_value());

 // First reference value: Original x-position. Used as the start point
 // for the lines connecting the nodes in the vertical direction
 double x_bottom=ref_value[0];
 
 // Second reference value: Fractional position along 
 // straight line from the bottom (at the original x position)
 // to the reference point on the upper wall
 double fract=ref_value[1];
 
 // Third reference value:  Reference local coordinate
 // in GeomObject that represents the upper wall (local coordinate 
 // in finite element if the wall GeomObject is a finite element mesh)
 Vector<double> s(1);
 s[0]=ref_value[2];

 // Fourth reference value: zeta coordinate on the upper wall
 // If the wall is a simple GeomObject, zeta[0]=s[0]
 // but if it's a compound GeomObject (e.g. a finite element mesh)
 // zeta scales during mesh refinement, whereas s[0] and the
 // pointer to the geom object have to be re-computed.
 // double zeta=ref_value[3]; // not needed here
      
 // Extract geometric objects for update by copy construction
 Vector<GeomObject*> geom_object_pt(node_pt->vector_geom_object_pt());
  
 // Pointer to actual wall geom object (either the same as the wall object
 // or the pointer to the actual finite element)
  GeomObject* geom_obj_pt=geom_object_pt[0];

 // Get position vector to wall at previous timestep t!
 Vector<double> r_wall(2);
 geom_obj_pt->position(t,s,r_wall);

 // Assign new nodal coordinate
 node_pt->x(t,0)=x_bottom+fract*(r_wall[0]-x_bottom);
 node_pt->x(t,1)=fract*r_wall[1];

}





//=====start_setup=================================================
/// Setup algebraic mesh update -- assumes that mesh has
/// initially been set up with a flush upper wall.
//=================================================================
template<class ELEMENT>
void AlgebraicFSIDrivenCavityMesh<ELEMENT>::setup_algebraic_node_update()
{


 // Loop over all nodes in mesh
 unsigned nnod=this->nnode();
 for (unsigned j=0;j<nnod;j++)
  {
   // Get pointer to node -- recall that that Mesh::node_pt(...) has been
   // overloaded in the AlgebraicMesh class to return a pointer to 
   // an AlgebraicNode.
   AlgebraicNode* nod_pt=node_pt(j);

   // Get coordinates
   double x=nod_pt->x(0);
   double y=nod_pt->x(1);
   
   // Get zeta coordinate on the undeformed wall
   Vector<double> zeta(1);
   zeta[0]=x;
   
   // Get pointer to geometric (sub-)object and Lagrangian coordinate
   // on that sub-object. For a wall that is represented by 
   // a single geom object, this simply returns the input.
   // If the geom object consists of sub-objects (e.g. 
   // if it is a finite element mesh representing a wall,
   // then we'll obtain the pointer to the finite element
   // (in its incarnation as a GeomObject) and the
   // local coordinate in that element.
   GeomObject* geom_obj_pt;
   Vector<double> s(1);
   this->Wall_pt->locate_zeta(zeta,geom_obj_pt,s);
   
   // Get position vector to wall:
   Vector<double> r_wall(2);
   geom_obj_pt->position(s,r_wall);
   
   // Sanity check: Confirm that the wall is in its undeformed position
#ifdef PARANOID
   if ((std::fabs(r_wall[0]-x)>1.0e-15)&&(std::fabs(r_wall[1]-y)>1.0e-15))
    {
     std::ostringstream error_stream;
     error_stream 
      << "Wall must be in its undeformed position when\n"
      << "algebraic node update information is set up!\n "
      << "x-discrepancy: " << std::fabs(r_wall[0]-x) << std::endl
      << "y-discrepancy: " << std::fabs(r_wall[1]-y) << std::endl;
     
     throw OomphLibError(
      error_stream.str(),
      OOMPH_CURRENT_FUNCTION,
      OOMPH_EXCEPTION_LOCATION);
    }
#endif       
   
   
   // One geometric object is involved in update operation
   Vector<GeomObject*> geom_object_pt(1);
   
   // The actual geometric object (If the wall is simple GeomObject
   // this is the same as Wall_pt; if it's a compound GeomObject
   // this points to the sub-object)
   geom_object_pt[0]=geom_obj_pt;
   
   // The update function requires four  parameters:
   Vector<double> ref_value(4);
   
   // First reference value: Original x-position 
   ref_value[0]=r_wall[0];
   
   // Second  reference value: fractional position along 
   // straight line from the bottom (at the original x position)
   // to the point on the wall)
   ref_value[1]=y/r_wall[1];
   
   // Third reference value: Reference local coordinate
   // in wall element (local coordinate in FE if we're dealing
   // with a wall mesh)
   ref_value[2]=s[0];   
   
   // Fourth reference value: zeta coordinate on wall
   // If the wall is a simple GeomObject, zeta[0]=s[0]
   // but if it's a compound GeomObject (e.g. a finite element mesh)
   // zeta scales during mesh refinement, whereas s[0] and the
   // pointer to the geom object have to be re-computed.
   ref_value[3]=zeta[0];     
   
   // Setup algebraic update for node: Pass update information
   nod_pt->add_node_update_info(
    this,               // mesh
    geom_object_pt,     // vector of geom objects
    ref_value);         // vector of  ref. values
  }
 

} //end of setup_algebraic_node_update 




////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////






//========start_update_node_update=================================
/// Update the geometric references that are used 
/// to update node after mesh adaptation.
//=================================================================
template<class ELEMENT>
void RefineableAlgebraicFSIDrivenCavityMesh<ELEMENT>::update_node_update(
 AlgebraicNode*& node_pt)
{
 // Extract reference values for node update by copy construction
 Vector<double> ref_value(node_pt->vector_ref_value());
 
 // First reference value: Original x-position 
 // double x_bottom=ref_value[0]; // not needed here
 
 // Second reference value: fractional position along 
 // straight line from the bottom (at the original x position)
 // to the point on the wall)
 // double fract=ref_value[1]; // not needed here
 
 // Third reference value:  Reference local coordinate
 // in GeomObject (local coordinate in finite element if the wall
 // GeomObject is a finite element mesh)
 // Vector<double> s(1);
 // s[0]=ref_value[2]; // This needs to be re-computed!
 
 // Fourth reference value: intrinsic coordinate on the (possibly 
 // compound) wall.
 double zeta=ref_value[3]; 
 
 // Extract geometric objects for update by copy construction
 Vector<GeomObject*> geom_object_pt(node_pt->vector_geom_object_pt());
 
 // Pointer to actual wall geom object (either the same as wall object
 // or the pointer to the actual finite element)
 //GeomObject* geom_obj_pt=geom_object_pt[0]; // This needs to be re-computed!
 
 // Get zeta coordinate on wall (as vector)
 Vector<double> zeta_wall(1);
 zeta_wall[0]=zeta;
 
 // Get pointer to geometric (sub-)object and Lagrangian coordinate
 // on that sub-object. For a wall that is represented by 
 // a single geom object, this simply returns the input.
 // If the geom object consists of sub-objects (e.g. 
 // if it is a finite element mesh representing a wall,
 // then we'll obtain the pointer to the finite element
 // (in its incarnation as a GeomObject) and the
 // local coordinate in that element.
 Vector<double> s(1);
 GeomObject* geom_obj_pt;
 this->Wall_pt->locate_zeta(zeta_wall,geom_obj_pt,s);
 
 // Update the pointer to the (sub-)GeomObject within which the
 // reference point is located. (If the wall is simple GeomObject
 // this is the same as Wall_pt; if it's a compound GeomObject
 // this points to the sub-object)
 geom_object_pt[0]=geom_obj_pt; 
 
 // First reference value: Original x-position 
 // ref_value[0]=r_wall[0]; // unchanged
 
 // Second reference value: fractional position along 
 // straight line from the bottom (at the original x position)
 // to the point on the wall)
 // ref_value[1]=y/r_wall[1]; // unchanged
 
 // Update third reference value: Reference local coordinate
 // in wall element (local coordinate in FE if we're dealing
 // with a wall mesh)
 ref_value[2]=s[0];
 
 // Fourth reference value: zeta coordinate on wall
 // If the wall is a simple GeomObject, zeta[0]=s[0]
 // but if it's a compound GeomObject (e.g. a finite element mesh)
 // zeta scales during mesh refinement, whereas s[0] and the
 // pointer to the geom object have to be re-computed.
 // ref_value[3]=zeta[0];     //unchanged
 

 // Kill the existing node update info
 node_pt->kill_node_update_info(); 
 
 // Setup algebraic update for node: Pass update information
 node_pt->add_node_update_info(
  this,               // mesh
  geom_object_pt,     // vector of geom objects
  ref_value);         // vector of ref. values
 
}



}
#endif