libxfoil is a library to analyze the aerodynamics of 2-dimensional airfoil sections programmatically using the Xfoil aerodynamics engine. The main focus is on supporting the functionality of Xfoil's OPER direct analysis mode, but some geometry functions including spline interpolation, flap deflections, trailing edge gap modifications, and NACA 4- and 5-digit airfoil generation are also included. In addition to integrated forces and moments, pressure distributions and boundary layer variables (including skin friction coefficient, displacement thickness, log of amplification ratio, etc.) can also be accessed.
The API employs a pseudo object-oriented approach; global variables in the original Xfoil code have been moved to a struct, allowing multiple instances of the Xfoil engine, representing different airfoils, to be saved in memory simultaneously and executed in parallel. Memory for each instance is managed dynamically through the xfoil_init and xfoil_cleanup methods. libxfoil provides C, Fortran, and Python bindings as well as example programs in each language.