Search Results (2)

Land-based airborne wind energy systems (LB-AWESs) offer a promising approach to harvesting high-altitude wind resources while significantly reducing costs. However, overall performance is heavily constrained by energy dissipation along the power chain, spanning from aerial traction to ground electromechanical conversion. While existing research and reviews predominantly focus on aircraft configurations or control strategies, comprehensive analyses of the energy transmission efficiency remain scarce. To fill this gap, this paper provides a holistic review of four critical stages: wind energy capture, tether transmission, ground mechanics, and electromechanical coupling. Distinct from traditional reviews centered on individual components, this study adopts a holistic perspective of the transmission chain to prioritize the analysis of loss mechanisms across different stages. In particular, it highlights that internal friction losses within multi-strand braided tethers under large-scale, cyclic loading conditions constitute a significant yet long-overlooked factor affecting energy transmission efficiency. Additionally, the stability and performance factors of umbrella-ladder configurations are qualitatively evaluated. By integrating existing theoretical studies, experimental findings and engineering practices, this paper identifies the key design factors affecting transmission efficiency, comprehensively elucidates the energy dissipation mechanisms of various subsystems, and proposes core efficiency enhancement methodologies, providing a foundational reference for the optimal design of next-generation LB-AWESs. Full article

As global demand for renewable energy continues to grow, high-altitude wind energy, characterized by high speed, wide distribution, and strong stability, has emerged as a promising alternative to low-altitude wind energy. Airborne Wind Energy systems (AWEs) are key to harnessing high-altitude wind, and Ground-Generator (Ground-Gen) AWEs are favored for their lower costs and simpler deployment. This study focuses on the umbrella–ladder-type Ground-Gen AWEs, aiming to address the research gap by exploring the influence of canopy permeability on the aerodynamic and structural response characteristics of flexible wind-capturing umbrellas. A single-umbrella model of the high-altitude wind-capturing umbrella was established, and bidirectional fluid–structure interaction (FSI) numerical simulations were conducted using the Arbitrary Lagrangian–Eulerian (ALE) method. Simulations were performed under a 30° angle of attack with two canopy thicknesses (5 × 10⁻⁵ m and 1 × 10⁻⁴ m) and varying permeability (adjusted via viscosity coefficient a and inertial coefficient b). Results showed that higher permeability (smaller a and b) hindered upper canopy inflation, while lower permeability promoted full inflation and more uniform stress distribution. The max/min in-plane shear stress for the model with the lowest permeability (Model F) was approximately 85% lower than that of the model with the highest permeability (Model A). The tension coefficient increased with decreasing permeability. Full inflation resulted in a slightly higher axial load in the upper suspension lines due to the lift force, with a difference of up to 92.3% during slight collapse. This difference becomes significantly more pronounced during severe collapse. Asymmetric flow fields at a 30° attack angle generated a lift force, resulting in higher tension coefficients than those at a 0° attack angle. These findings provide valuable references for the design and optimization of high-altitude wind-capturing umbrellas. Full article