Development of Vortex Filament Method for Wind Power Aerodynamics
Doktorsavhandling, 2016

Wind power is currently one of the cleanest and widely distributed renewable energy sources serving as an alternative to fossil fuel generated electricity. Exponential growth of wind turbines all around the world makes it apt for different research disciplines. 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 its relation to rotor structural dynamics is crucial for design, development and optimization purposes. This leads us to focus on high-fidelity modeling of the rotor and wake aerodynamics. There are different methods for modeling the aerodynamics of a wind turbine with different levels of complexity and accuracy, such as the Blade Element Momentum (BEM) theory, Vortex method and Computational Fluid Dynamics (CFD). Historically, the vortex method has been widely used for aerodynamic analysis of airfoils and aircrafts. Generally, it may stand between the CFD and BEM methods in terms of the reliability, accuracy and computational efficiency. In the present work, a free vortex filament method for wind turbine aerodynamics was developed. Among different approaches for modeling the blade (e.g. a lifting line or a lifting surface) and wake (e.g. a prescribed or a free wake model), the Vortex Lattice Free Wake (VLFW) model known as the most accurate and computationally expensive vortex method was implemented. Because of the less restrictive assumptions, it could be used for unsteady load calculations, especially for time-varying flow environment which are classified according to the atmospheric conditions, e.g. wind shear and turbulent inflow together with the turbine structure such as yaw misalignment, rotor tilt and blade elastic deformation. In addition to the standard potential method for aerodynamic load calculation using the VLFW method, two additional methods, namely the 2D static airfoil data model and the dynamic stall model were implemented to increase capability of the free vortex wake method to predict viscous phenomena such as drag and separation using tabulated airfoil data. The implemented VLFW method was validated against the BEM and CFD methods, the GENUVP code by National Technical University of Athens (NTUA), Hönö turbine measurement data and MEXICO wind tunnel measurements. The results showed that the VLFW model might be used as a suitable engineering method for wind turbine’s aerodynamics covering a broad range of operating conditions.

unsteady aerodynamic load

atmospheric turbulence

fatigue loads

Free wake model

forest canopy

wind turbine

vortex method

large-eddy simulation

HA3, Hörsalsvägen 4, Campus Johanneberg
Opponent: Prof. Jens N. Sørensen, Department of Wind Energy, Technical University of Denmark, Denmark

Författare

Hamidreza Abedi

Svensk Vindkraftstekniskt Centrum (SWPTC)

Chalmers, Tillämpad mekanik, Strömningslära

Development of Free Vortex Wake Model for Wind Turbine Aerodynamics under Yaw Condition

34th Wind Energy Symposium, 2016; San Diego; United States; 4 January 2016 through 8 January 2016,; (2016)

Paper i proceeding

Numerical Studies of the Upstream Flow Field around a Horizontal Axis Wind Turbine

33rd Wind Energy Symposium, Kissimmee, Florida,; (2015)p. 12-

Paper i proceeding

Development of Free Vortex Wake Method for Aerodynamic Loads on Rotor Blades

EWEA 2014: Europe’s Premier Wind Energy Event, Barcelona, Spain,; (2014)

Paper i proceeding

Development of Free Vortex Wake Method for Yaw Misalignment Effect on the Thrust Vector and Generated Power

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

Paper i proceeding

Vortex Method Application for Aerodynamic Loads on Rotor Blades

EWEA 2013: Europe’s Premier Wind Energy Event, Vienna, 4-7 February 2013,; Vol. 2(2013)p. 912-921

Paper i proceeding

Ämneskategorier

Maskinteknik

Strömningsmekanik och akustik

ISBN

978-91-7597-360-9

Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 4041

HA3, Hörsalsvägen 4, Campus Johanneberg

Opponent: Prof. Jens N. Sørensen, Department of Wind Energy, Technical University of Denmark, Denmark