Development of Free Vortex Wake Method for Yaw Misalignment Effect on the Thrust Vector and Generated Power
Paper in proceeding, 2014

Wind power is currently one of the most reliable new energy sources serving as an alternative to fossil fuel generated electricity and is known as a widely distributed clean and renewable source of energy. It is now the world's fastest growing energy source and has also become one of the most rapidly expanding industries. The aerodynamics of a wind turbine is governed by the flow around the rotor, where the prediction of air loads on rotor blades in different operational conditions and their relation to rotor structural dynamics is crucial for design purposes. One of the challenges in wind turbine aerodynamics is the yaw condition where the undisturbed upstream flow is not perpendicular to the rotor plane, giving a non-uniform blade load which is contrary to the axisymmetric flow assumption in the BEM (Blade Element Momentum) method. However, there are some engineering methods modifying the BEMmethod for yaw misalignment situations,1 where they often calculate the skewed axial induction factor as an average value over the rotor disk which is insensitive to the blade rotation direction. On the other hand, experiments show that the thrust vector for a positive yaw misalignment differs from that for a negative yaw misalignment. A free vortex wake method, based on the potential, inviscid and irrotational flow, is developed to study the deviation of thrust vector relative to rotor shaft. The results are compared with the BEM method2 and experimental data. A two-bladed variable speed wind turbine, the Hönö wind turbine,3 is used for this study.

Structural dynamics

Boundary element method

Operational conditions

Engineering methods

Wind power

Wind turbine aerodynamics

Blade-element momentums

Wind turbines Alternative to fossil fuels

Misalignment effects


Variable speed wind turbines

Free vortex wake methods


Hamidreza Abedi

Swedish Wind Power Technology Center (SWPTC)

Chalmers, Applied Mechanics, Fluid Dynamics

Lars Davidson

Chalmers, Applied Mechanics, Fluid Dynamics

Swedish Wind Power Technology Center (SWPTC)

Spyros Voutsinas

National Technical University of Athens (NTUA)

32nd AIAA Applied Aerodynamics Conference 2014; Atlanta, GA; United States; 16 June 2014 through 20 June 2014

Subject Categories

Aerospace Engineering



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