Advances in Wind Turbine Analysis and Design for Sustainable Energy

Georgia Tech Research Corporation, Atlanta GA

Investigators

Abstract

Wind energy is expected to be a major source of sustainable energy in the coming years as this country transitions from traditional carbon-based fuels such as coal and nature gas. Before national wind turbine acceptance and utilization can be realized, several specific technical issues must be addressed. Of these, the greatest challenge is the reduction of noise pollution by the turbines while maintaining performance. The primary source of noise is generated by aerodynamic effects and is known as aeroacoustic noise. Various factors influence the strength of the aeroacoustic noise including inflow turbulence, turbine blade elasticity and tip speeds. The prediction of their relative effects is incredibly challenging and draws upon a multiple engineering fields: aerodynamics, turbulence, structural dynamics, material and atmospheric sciences, etc. Intellectual merit: This proposed effect will advance the state-of-the-art in computational modeling techniques for both fixed and rotating aerodynamic systems, as applied to wind turbine analysis and design. The computational tools developed within this work advance the following: (i) the fidelity of wall-bounded, unsteady flow simulations by creating an adaptable turbulence modeling method, (ii) the efficiency and exact- ness of the coupling process between computational fluid dynamics and computational structural dynamics (CFD-CSD) simulations, so improved fluid-structure interaction effects can be included in aero-acoustic studies, and (iii) the effectiveness of adaptive mesh refinement methods for unsteady, moving-body flow simulations. These advances will be verified via correlations with existing experimental and computational data. These tools will be demonstrated in design applications of interest to the wind turbine community. Broader Impact: If successful, proposed research endeavor will have a significant and tangible impact on the effective design of moderate- to large-scale wind turbines. Current design methods rely heavily on empirical rules-of-thumb due to a lack of effective predictive tools. The technology transferred to the wind energy industry will assist in predicting and reducing noise pollution generated by the large turbines, a major hindrance in wind farm deployment, and by smaller turbines utilized in or near inhabited areas. Reducing the noise pollution to a less objectionable level, while maintaining or improving current turbine performance characteristics, will allow greater utilization of vast stretches of windy terrain not altogether isolated from the population for which it is providing power. Closure proximity to population areas will shorten transmission lines and reduce the associated losses. Furthermore, quieter blades/tips would enable increases in tip-speed ratios which will permit lighter drive-trains leading to lower deployment costs. More efficient design of large- and moderate-scale wind turbines will also positively impact the globalization of this sustainable energy source, in particular in developing third-world nations. The results of this research will be presented at international conferences and published in journal publications. In addition, the information will be made available via the GIT Aerospace Digital Library in formats compatible for both the engineering and general community. Results of the research will also be incorporated into both graduate and undergraduate courses at Georgia Tech as examples and case studies.