Airfoil data

Rotare requires the input of airfoil polars to properly interpolate the lift and drag coefficient of each element. These polars can be directly provided or generated using external tools such as XFOIL or XFLR5.

The following process explains how to generate such polars and transform them in a structure to be imported in Rotare. A more complete description is provided in the complete manual of Rotare.

polargenerator.py

polargenerator is a small script that will run XFOIL in order to generate the airfoil polars. This script uses the aeropy library, follow the instructions on the Github to install it properly. (_Note: this is not the same aeropy than the one installed through pip).

The usage is straightforward:

python polargenerator <airfoil>

It can either accept a NACA airfoil as input or a file with the airfoil coordinates. Example:

python polargenerator 'naca0012'
python polargenerator 'myairfoil.dat'

Note that if the airfoil coordinates are provided though a DAT-file, the need to be formatted according to the Selig convention (see "Airfoil Format" section on the UIUC Airfoil Database). A Matlab utility is provided with the af_tools library to convert the Ledneicer format into Selig format.

MAT-file

Once the raw XFOIL data have been generated for a given airfoil, they need to be converted into a structure that will be understood by Rotare. This is done using the xf2mat function provided by the af_tools library.