Getting started with ElmerGUI

From Elmer Wiki
Jump to: navigation, search

This quick start tutorial describes how to solve the heat equation in an L-shaped domain in 3D with ElmerGUI.

Basic steps

  • Start ElmerGUI
  • Choose "File -> Open..." Select the sample input file "angle3d.grd".
    • On Windows machines, the file is located in "C:\Elmer5.4\samples\ElmerGUI\samples\grd"
    • On Linux, the file is in the source tree in "trunk/misc/Mesh3D/samples/grd".
angle3d.grd
  • Choose "Model -> Equation -> Add..."
    • In the "Heat equation" tab, check the "Activate" box.
    • In the "Apply to bodies:" group, check the "Body 1" box.
    • Press "OK".
  • Choose "Model -> Material -> Add..."
    • In the "General" tab, set value "1" in the "Density" edit box.
    • In the "Heat equation" tab, set value "1" in the "Heat Conductivity" edit box.
    • In the "Apply to bodies:" group, check the "Body 1" box.
    • Press "OK".
  • Choose "Model -> Body force -> Add..."
    • In the "Heat equation tab", set value "1" in the "Heat source" edit box.
    • In the "Apply to bodies:" group, check the "Body 1" box.
    • Press "OK".
  • Choose "Model -> Boundary condition -> Add..."
    • In the "Heat equation tab", set value "0" in the "Temperature" edit box.
    • In the "Apply to boundaries:" group, check the "Boundary 3" box.
    • Press "OK".
  • Choose "Sif -> Generate"
  • Choose "File -> Save as..." Select a work directory and press "OK".
  • Choose "Run -> Run solver".
  • Choose "Run -> Run postprocessor"
  • If you want to save the contents of your ElmerGUI-project, choose "File -> Save project...".
  • You can then resume working with the current settings by choosing "File -> Load project...".

Rotate, pan, zoom

  • Rotate: press the left mouse button and move the mouse.
  • Pan: press the middle mouse button and move the mouse.
  • Zoom: press the right mouse button and move the mouse.

Mesh refinement

  • Choose "Mesh -> Configure..." and set "-relh 0.2" in the "elmergrid string" edit box.
  • Press "Close" and select "Mesh -> Remesh".
  • Choose "File -> Save" and "Run -> Run solver" to resolve the problem.
  • If you are using Tetgen as a mesh generator, the mesh density can be controlled by choosing "Mesh -> Control..." and entering a control string in the "tetlib string" edit box. The syntax of the control string is discussed in Tetgen's manuals. Similarly for Netgen.

Controlling numerical methods

  • Choose "Model -> Equation -> Equation 1" and press the "Edit Solver Settings" button.
  • Select the numerical methods/parameters you wish to use and press "Apply".
  • Close the equation editor by pressing the "OK" button.
  • Finally, choose "Sif -> Generate" and "File -> Save" to save the changes.
  • Solve the problem by choosing "Run -> Run solver".

Redefining boundary conditions and body properties

  • Holding down the ALT-key while double clicking a boundary will make the boundary property menu pop up. Choose a boundary condition and press "Add" to assign a condition to the highlighted boundary part. You can also remove boundary conditions by pressing the "Remove" button.
  • Holding down the SHIFT-key while double clicking a body will make the body property menu show up. From this menu, you can choose material etc. properties to assign to the body.
  • Finally, choose "Sif -> Generate" and "File -> Save" to save the changes.
  • Choose "Run -> Run solver" to solve the problem.

Notes

  • You must always choose "Sif -> Generate" and "File -> Save" after having changed or edited any menu items. Otherwise, the changes do not become effective in the solution phase. Another possibility to make changes is to directly edit the SIF-file by choosing "Sif -> Edit..." and "File -> Save".
  • The menu entries "File -> Save" and "File -> Save as..." will save the mesh files (mesh.*) and solver input file (*.sif) for ElmerSolver. ElmerGUI's work space and menus are not saved in this case.
  • The menu entry "File -> Save project..." will save ElmerGUI's work space and contents of the menus. Mesh files (mesh.*) and solver input file (*.sif) are not saved.
  • The menu entry "File -> Open..." will open an geometry input file and feed it to the mesh generator.
  • The menu entry "File -> Open model..." will read in Elmer's mesh files (mesh.*).
  • The menu entry "File -> Load project..." will read in a previously saved work space and set up the menus as they were when the project was saved.