AUTHOR=Zhang Yuquan , Ji Renwei , Sun Ke , Zhang Zhi , Zheng Yuan , Zhang Jisheng , Zhang Xuewei , Rodriguez Emmanuel Fernandez 

TITLE=Research on complex wake interference of aligned rotors considering the precone variation of the upstream wind turbine

JOURNAL=Frontiers in Marine Science

VOLUME=Volume 9 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2022.1039233

DOI=10.3389/fmars.2022.1039233

ISSN=2296-7745

ABSTRACT=To understand the flow effects of horizontal-axis wind turbines, a high-fidelity and low-cost wake simulation framework (AL-LDS coupling model framework) is developed by combining the actuator line (AL) with a localized dynamic Smagorinsky (LDS) sub-grid model. In this approach, an LDS sub-grid model is initially programmed and implanted, and its accuracy and advantages are validated by comparing with the benchmark results of a classical Bluff-body flow case. Secondly, the benchmark values of the NREL-5MW wind turbine are selected to validate the accuracy of the AL-LDS coupling model. Finally, the research is extended to predict the interference between two tandem rotor wakes. The influence of the precone characteristics on the overall wake and power output of the tandem wind turbines is explored by modifying the upstream wind turbine and introducing the latest third-generation NewOmega vortex identification method for the first time in the post-processing procedure. According to results, the tandem wind turbines have complex wake interference, with the precone angle variation improving the output power of the upstream wind turbine, to the disadvantage of a strong downstream turbine wake. Under the same turbines precone angle scenario, the negative precone change of the upstream wind turbine is more conducive to the overall power output of the tandem rotors. Despite the optimal precone angle of the upstream wind turbine is 0°, a -2.5° proves more advantageous due to the large flexible deformation of the wind turbine blade tip. The findings can serve as a continuous incentive for improving wind farm numerical simulation.