Optimized empty duct geometry for ducted wind turbines: A prairie dog burrow-inspired approach

Urban wind energy, as a potential renewable energy source, has garnered increasing attention for its complementary role in wind energy mix. However, the low speeds and high turbulence intensity of urban wind pose significant challenges to the efficient energy harvesting of conventional wind turbines. To address these limitations, this study proposes a new duct design inspired by prairie dog burrows for ducted wind turbines. Through numerical simulations and a single-factor analysis, this work systematically investigates the effects of twelve geometric parameters on wind speed and turbulent kinetic energy within the bio-inspired duct, enabling the optimization of the duct's geometry. Results demonstrate that the bio-inspired protrusion significantly enhances wind speed within the duct. Specifically, the nozzle and venturi-shaped duct achieve optimal performance with smaller radii and longer lengths. The diffuser duct radius proves critical for mitigating flow separation and homogenizing pressure distribution. Compared to a conventional duct, the optimized bio-inspired duct demonstrates a 41.4 % enhancement in average maximum wind speed. To evaluate the bio-inspired ducted wind turbine performance, field measurements reveal that the proposed design exhibits a 117 % increase in power coefficient compared to a bare turbine. Furthermore, this study discusses the potential challenges associated with bio-inspired ducts in future work.