An assessment of compressibility effects for large wind turbines using the blade element momentum method

Abstract

Compressibility effects for modern wind turbines become more and more important as turbines being built are getting bigger and bigger. Assessment of the compressibility effects on the blade aerodynamics of a 2.3-MW and 3.0-MW wind turbine using the Blade Element Momentum (BEM) method shows that, compressibility effects will degrade the turbine performance only at extreme operating conditions, it is safe to use incompressible aerodynamic properties when modeling normally operating large wind turbines. A simple assessment of air density, on the other hand, shows that it will affect power production in a more direct way than blade aerodynamic properties. Thus when modeling a large wind turbine, either a more accurate choice of the reference density or a compressible framework should be used.