, Volume 26, Issue 3, pp 827-838

Design optimization of a wind turbine blade to reduce the fluctuating unsteady aerodynamic load in turbulent wind

Abstract

Design optimization of the wind turbine of a NREL 1.5-MW HAWT blade was studied to minimize the fluctuation of the bending moment of the blade in turbulent wind. In order to analyze the unsteady aerodynamic load of a wind turbine, FAST code was used as the analysis code. To consider turbulent wind as the wind input model in FAST, TurbSim was used as a turbulent wind simulator. For effective geometrical representation of the aerodynamic shape of a wind turbine blade, the shape modeling function was used to represent the chord length and twist angle. The fluctuation of the out-of-plane bending moment at the blade root was minimized by maintaining the required power of the wind turbine. Through the redistribution of the section force in the radial direction between both the primary and tip regions, the magnitude of the fluctuation of the out-of-plane bending moment was reduced by about 20%, and the rated power of 1.5-MW was maintained. The local angles of attack for the optimized blade were near the point of the maximum lift-to-drag ratio in the primary and tip regions compared to the baseline blade. The fluctuating unsteady aerodynamic load in the optimized blade was reduced within the operating range of the wind speed. With the optimized blade shape, the wind turbine can be operated with decreased fluctuating aerodynamic loads and have a longer life in turbulent wind.

This paper was recommended for publication in revised form by Associate Editor Do Hyung Lee
Jihoon Jeong is a Ph.D candidate in aerospace engineering at Seoul National University. His B.S degree is from Seoul National University. His research interests include multidisciplinary design optimization and reliability-based design optimization for complex systems.
Dong-Ho Lee is a professor in School of Mechanical and Aerospace Engineering at Seoul National University. He is a member of The National Academy of Engineering of Korea. He is interested in computational fluid dynamics, wind tunnel test and multidisciplinary design optimization for large and complex systems (e.g. aircraft, helicopter, high speed train, compressor, and wind turbine).