Hardening Advanced Methods for Predicting 3D Unsteady Flows Around Wind Turbines for Industrial Use

Wind power plays an increasingly important role in satisfying the power needs of the United States. With increased market penetration, unanticipated unsteady loading induced failures, installation related reductions in power generation and significant maintenance costs have underscored the need to predict the unsteady fluid structure interactions related to turbine layout and off-design wind conditions. Contemporary turbine design tools fail to account for such loadings, and thus, the research community has started utilizing HPC Computational Fluid Dynamics (CFD) solvers to investigate these phenomena. Unfortunately, such HPC tools are too computationally expensive for routine industrial use. This problem is exacerbated further for wind turbines given the unsteady coupling between blade motion, flexibility, wake aerodynamics and the interaction with the turbulent atmosphere. In an ongoing DOE STTR Phase II an advanced method for predicting wind turbine fatigue and wind farm aeromechanics has been developed. This effort successfully demonstrated improved analysis capabilities and enhanced ease- of-use and integration with other CFD software; however scalability bottlenecks related to oversetting mixed formulation CFD solvers limit application of the software to canonical problems by expert users. The proposed Phase IIB builds upon this work by tackling these limitations, and will transition these DOE sponsored numerical methods to industry. The proposed effort addresses the bottlenecks that inhibit scalability of the overset CFD-based method developed in the initial Phase II through algorithm improvement and rehosting core flow solver algorithms within scalable adaptive grid software frameworks that are part of several ongoing numerical methods development efforts underway within DOE. By adopting DOE supported software libraries and ensuring compatibility with CFD frameworks that are in use and being adopted by the wind energy industry, the proposed software will have a seamless transition path to community adoption. Commercial Applications and Other Benefits: A successful effort would produce a robust and efficient computational tool for wind turbine design and analysis that directly addresses the limitations of current analysis techniques for predicting unsteady turbine blade loading and situational interactions. Based upon a modest market entry, combined sales and associated service work could generate ~$50M in cumulative revenue within ten years, with major cost savings for manufacturers and end users from improved predictions and lower maintenance costs. Moreover, as is evidenced by the included letter of support, additional commercialization is anticipated through application to other vorticity dominated flows such as rotorcraft and bluff-bodies.