Abstract The twin vertical-axis wind turbine (VAWT) system is a high-performance design in which two turbines are placed side by side with a variable gap distance. In this paper, the large eddy simulation and the sliding mesh technique are employed to numerically study the aerodynamic performance of the dual-rotor configuration. First, the reliability of this CFD model is validated, including computational stability analysis, time-step dependency study, and grid convergence verification. The turbine power coefficients under different tip speed ratios are calculated and results exhibit a satisfactory agreement with the available experimental data. Then, the wind energy utilization of side-by-side placed twin VAWTs under different gap ratios and various azimuth angle shifts are investigated, respectively. The results reveal that compared with two isolated turbines, the power coefficient of a twin-turbine system has a significant enhancement. Moreover, the paper analyzes the mechanism for obtaining gains. In regard to the study of azimuth angle shifts between two adjacent turbines, this paper demonstrates that the blade azimuth angles of twin VAWTs do not need to be synchronized. The azimuth angle shift has little effect on the aerodynamic performance of the twin-turbine system.

中文翻译：

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并排放置的双垂直轴风力机气动分析

摘要 双垂直轴风力涡轮机（VAWT）系统是一种高性能设计，其中两个涡轮机并排放置，间隙距离可变。本文采用大涡模拟和滑动网格技术对双旋翼结构的气动性能进行数值研究。首先，验证了该 CFD 模型的可靠性，包括计算稳定性分析、时间步长依赖性研究和网格收敛验证。计算了不同叶尖速比下的涡轮功率系数，结果与可用的实验数据具有令人满意的一致性。然后，分别研究了并排放置的双VAWT在不同间隙比和各种方位角偏移下的风能利用。结果表明，与两个孤立的涡轮机相比，双涡轮机系统的功率系数有显着提高。此外，本文还分析了获得收益的机制。针对相邻两台涡轮机之间方位角偏移的研究，本文论证了双VAWT的叶片方位角不需要同步。方位角偏移对双涡轮系统的气动性能影响不大。