Python interface for AVL and XFOIL
AVL and XFOIL are efficient and reliable tools for low-fidelity analysis of lifting surfaces. Chrysopelea is intended to provide a convenient way to use these tools from Python scripts, which is ideal for sizing and stability analysis during preliminary design. The object oriented framework makes it feasible to extend this interface to incorporate other data or design considerations. Finally, it saves the headache of editing AVL files by hand, which is no trivial matter, especially when constructing complex planforms.
Chrysopelea is intended for convenience. It is not currently optimized for execution speed. It is meant to be as intuitive as possible for all users. However, it may still be much easier to understand if the user has basic proficiency with the command line interface of AVL and XFOIL.
Chrysopelea (Wikipedia), aka "flying snake" is a genus of snakes that can glide from trees to the ground by extending their ribs to flatten the cross section of their body. A flying snake seemed to be a suitable namesake for a Python program for analyzing aircraft.
Currently supports:
- Creation of aircraft configurations employing most features supproted by AVL.
- Creation of 2D wing sections from coordinate files or NACA designations.
- Calculation of 3D, inviscid aerodynamic properties, including stability derivatives, with AVL.
- Total drag estimates combining AVL predictions for induced drag with XFOIL predictions for 2D section drag.
- Moment, trim, and static stability calculations.
- Calculation of derived geometric properties, including aspect ratio and mean aerodynamic chord.
- Calculation of lift and bending moment distributions.
- Geometry and Treffitz plots.
- Reading and writing AVL files. (Reading human-generated files is still a bit unreliable).
Users must supply their own copies of AVL and XFOIL. They may specify the command or executable file used to invoke AVL and XFOIL by setting the class
attributes Avl.avl_cmd and Section.xfoil_cmd respectively. Python dependencies are:
- Python 3
- Python libraries:
- matplotlib
- pandas
In order to use Chrysopelea, you just need to ensure that Python can find its files.
The way I do this is I have a directory (~/programs/python) that I added to my PYTHONPATH in which I install python codes.
In this case, you can install Chrysopelea with the command cp *.py ~/programs/python (executed in the Chrysopelea root directory).
Alternatively, you could add the Chrysopelea root directory to your PYTHONPATH or just copy the files to the directory where you want to use them.
Documentation is in progress. For now, the file tests/test_avl.py demonstrates most of the important features. tests/test_section.py demonstrates how
Section can be used as a stand-alone XFOIL interface.
Feedback or contributions regarding problems or new features are welcome. Please contact Micaiah at micaiah@smithpierce.net or micaiah@gatech.edu.