Titel: Optimization of Semi-Empirical Parameters in the FFA-Beddoes Dynamic Stall Model, FFA TN 1999-37
Författare: Murat Mert
Utgivare: Flygtekniska Försöksanstalten
Årtal: 1999
Ämnesord: Mekanik och aerodynamik
Sökord/keyword: aerodynamic effects, wind turbines, stall model, 2D wind tunnel, MMA, vindforsk.
Rapport (Pdf)

Sammanfattning/Abstract: Unsteady aerodynamic effects, like dynamic stall, must be considered in calculation of dynamic forces for windturbines. Models incorporated in aero-elastic programs are of semi-empirical nature. Resulting aerodynamic forces therefore depend on values used for the semi-empirical parameters. In this report a study of finding appropriate parameters to use with the FFA- Beddoes-Leishman dynamic stall model is discussed. Minimization of the deviation between results from 2D wind tunnel tests and simulation with the model is used to find optimum values for the parameters.

The optimization program MMA, Method of Moving Asymptotes is used to optimize parameters in the model for nonlinear aerodynamics.

The optimization program MMA has been modified to work for problems with a quadratic object function without constraints.

The resulting optimum parameters show a large variation from case to case. Using these different sets of optimum parameters in the calculation of blade vibrations give rise to quite different predictions of aerodynamic damping.