GDTk: The Gas Dynamic Toolkit

GDTk: The Gas Dynamics Toolkit

The Gas Dynamics Toolkit is a collection of programs and functions for computing the properties of high-speed gas flows. Since the computational tools have been developed within the University of Queensland’s Centre for Hypersonics, there is clear bias toward predicting chemically-reacting gas flows, as would be found in shock-tunnel and expansion-tube experiments.

The computational tools range from large-scale programs for the simulation of gas flows in whole experimental facilites and more limited functions for the evaluation of simple state-to-state transitions, such as the jump in flow conditions across a simple shock wave.

The principal developers of these tools are Peter Jacobs, Rowan Gollan, Ingo Jahn, Anand Veeraragavan and Vince Wheatley. There have been many more contributors to the project over the years, including colleagues at other universities, students and visitors. A list of some of those contributors is available here.

The principal tools in the kit are:

  • Eilmer, a simulation program for 2- and 3-dimensional gas flows.
  • L1d, a program for the end-to-end simulation of free-piston-driven shock tunnels and expansion tubes.
  • IMOC, an interactive program for the isentropic method for characteristics for 2-dimensional ideal gas flows.
  • A library of functions for the calculation of simple gas dynamic processes such as shocks and expansions in the presence of chemical reactions. This library may be used from within your Lua scripts, or a version of it may loaded into a Python or Ruby interpreter. The Poshax program is an example of a Python program that makes use of the functions from the library.

How to get started

The complete repository is available on bitbucket:

It is worth browsing the Getting started introduction and trying the starting exercise described there.


The codes and documentation in the this toolkit are freely available.

  • For the source code within the toolkit, we use the GNU General Public License 3. Please see the file gpl.txt in the source tree.
  • For the documentation, such as this website and the user guides, we use the Creative Commons Attribution-ShareAlike 4.0 International License.

How to cite

We hope that, by using Eilmer and the other tools, you are able to produce some high quality simulations that aid your work. When it comes time to report the results of your simulations to others, we ask that you acknowledge our work by citing our papers on the codes.

How can you contribute

  • By using the code and giving us feedback on your simulations and results.
  • By giving us feedback on the documentation.
  • By contributing source code.