TWOD_TO_VTU
Write 2D Finite Element Data to VTU File

TWOD_TO_VTU is a MATLAB program which accepts a certain set of 2D finite element data and writes it to a VTK unstructured grid file for postprocessing by PARAVIEW.

The finite element data is assumed to be given in terms of:

• the xy coordinates of a set of nodes;
• the (1-based) indices of nodes that form triangular elements;
• the values of U, V, and P at each node (velocity components and pressure).

Since the VTK format expects 3D data, this program appends a 0 value to coordinate and vector data, where appropriate. It also changes the triangular element definitions so that the node indices are 0-based.

Information about PARAVIEW is available at http://www.paraview.org/ .

Licensing:

The computer code and data files described and made available on this web page are distributed under the GNU LGPL license.

Related Data and Programs:

NS3D_FEM, a MATLAB program which sets up and solves a finite element formulation of the steady incompressible 3D Navier Stokes equations on a user-defined geometry. The program can output graphics files for TECPLOT, VU or the VTK format used by PARAVIEW.

THREED_TO_VTU, a MATLAB program which accepts computational data from a 3D finite element fluid flow program and writes it to a VTK unstructured grid file for postprocessing by PARAVIEW.

TWOD, a MATLAB library which contains functions useful for 2D finite element calculations.

TWOD_TO_VTK, a MATLAB program which accepts computational data from a 2D finite element fluid flow program and writes it to a VTK "legacy" file for postprocessing by PARAVIEW.

VTU, a data directory which contains examples of VTU files, an XML-based file format used by the Visual Toolkit for unstructured grids, and which can be displayed by the PARAVIEW program;

Reference:

1. Will Schroeder, Ken Martin, Bill Lorensen,
   The Visualization Toolkit, An Object-Oriented Approach to 3D Graphics,
   Prentice Hall, 1998,
   ISBN: 0139546944,
   LC: QA76.64.S36.
2. Amy Henderson Squillacote,
   The ParaView Guide,
   Kitware Inc, 2007,
   ISBN13: 978-1-930934-21-4.
3. Will Schroeder, Ken Martin, Lisa Avila, Charles Law,
   The Visualization Toolkit User's Guide,
   Kitware Inc, May 2000,
   ISBN13: 978-1930934030.
4. http://public.kitware.com/VTK/

Source Code:

• timestamp.m, prints the YMDHMS date as a timestamp.
• two_to_vtu.m, writes out a 2D finite element solution.

Examples and Tests:

• twod_to_vtu_test.m, a MATLAB function which runs a test of TWOD_TO_VTU.

CHANNEL is finite element data associated with a 4 by 11 grid of points in a 3x10 rectangular channel, the triangular elements formed from those nodes, and the velocity and pressure of an associated Poiseuille flow solution.

• channel_nodes.txt, the coordinates of the nodes;
• channel_elements.txt, the element definitions;
• channel_values.txt, the values of U, V and P at each node.
• channel.vtu, the VTU file created from this data by the TWOD_TO_VTU_TEST function.

You can go up one level to the MATLAB source codes.