High-efficiency bi-directional wind energy harvesting based on wake interactions in bluff body tandem configuration

Abstract

To address the limitation of unidirectional wind energy harvesters (WEHs) in omnidirectional scenarios, this study introduces a high-efficiency bi-directional wind energy harvester based on wake interactions in bluff body tandem configuration (BWEH-WI). Different from traditional unidirectional and single bluff body structures, the proposed system comprises both outer and inner bluff bodies connected in tandem, each with a distinct cross-section. By harnessing the inherent aerodynamic characteristics of the bluff bodies and the wake interaction phenomenon, bi-directional energy harvesting is realized for both the inner and outer systems. To predict the dynamic behaviors, a coupled aero-electro-mechanical model is developed, dynamics mesh simulations and lift curve analysis are utilized to define the aerodynamic characteristics of the interaction mechanism. Additionally, wind tunnel experiments are carried out to analyze the aerodynamic interactions between the bluff bodies by varying the configurations and gap distances. The mathematical model is validated by comparing the experimental and theoretical results, showing good agreement. The experimental results indicate that the outer bluff body has a dominant influence on the inner bluff body in the negative wind direction, which is the primary cause of the inner bluff body’s periodic vibration. The proposed system exhibits excellent performance with a significant power increase of 116.4 % compared to the conventional single bulb-shaped energy harvester. Overall, this study provides valuable insights and design guidance for achieving bi-directional energy harvesting under the influence of the wake interactions. These findings contribute to the advancement of energy harvesting technology and are of significance for self-powered smart monitoring systems.