NWTC has developed a suite of turbine design and performance prediction codes which rely on Blade Element Momentum (BEM) theory.
FAST is a comprehensive aero-elastic simulator which uses unsteady BEM theory to model a turbine as a collection of rigid and flexible bodies in a spatiotemporal field of turbulent flow.
Germanischer Lloyd found FAST suitable for "the calculation of onshore wind turbine loads for design and certification.
The open source software Vortexje, developed by Baayen & Heinz GmbH in Berlin, is an unsteady 3D panel method implementation suitable for dynamic simulation of vertical and horizontal axis wind turbines.
Ashes is a software package for analyzing aerodynamic and mechanical forces for onshore and offshore horizontal axis wind turbines.
The user can usually input wind data, height and roughness contour lines (topography), turbine specifications, background maps, and define environmental restrictions.
Processing this information produces the design of a wind farm that maximizes energy production while accounting for restrictions and construction issues.