A novel wake energy reuse method to optimize the layout for Savonius-type vertical axis wind turbines

The long wake of a wind turbine has a significant impact on the performance of downstream turbines. Under the inspiration of migrating geese flying in a V or I formation to save energy, a novel wake energy reuse method is proposed to optimize the layout for Savonius-type vertical axis wind turbines (S-VAWT). VAWT wakes include a series of high speed and energy zones. On both sides of the upstream turbine, 7 x 16 transient two-dimensional numerical simulations are performed with Fluent to investigate wake structure, interaction effect and power coefficients (C-p) of downstream turbines. Based on Kriging Method, a response surface model (Surrogate model) is created to describe the relationship between the optimization objective Cp and layout positions. Finally, particle swarm optimization algorithm is applied to find the optimal relative layout position (5.25 m, -2.18 m) of the downstream turbine. The optimal position is located in the periodic high speed zone of the wake on the advancing blade side. And the optimal position is suitable for multi-turbines in a large wind farm. The optimization results show that Cp of downstream turbines at optimal layout position is significantly increased from 0.2477 to 0.3044 (22.89% higher). (C) 2017 Elsevier Ltd. All rights reserved.