Effect of discontinuous biomimetic leading-edge protuberances on the performance of vertical axis wind turbines

The clustering distribution of vertical axis wind turbines in limited sea areas is a hot direction in offshore wind power. This study attempts to use biomimetic protuberances to improve the low efficiency of individual vertical axis wind turbines. It provides, for the first time, insights into the influence of spacing between protuberances on the performance of biomimetic blades. The aerodynamic performance of six biomimetic blade designs with continuous and discontinuous leading-edge protuberances is explored under conditions of tip speed ratios of 1.5, 2.19, and 3. The results show that blades with long-wavelength protuberances perform better, with a 6.28% increase in power coefficient for blades with continuous three protuberances. Under the condition of long-wavelength, blades with continuous protuberances perform better than those with discontinuous protuberances. By comparing the cross-sectional averaged power coefficient of each blade, the impact of protuberances wavelength and spacing on sectional performance is further explored. The study reveals that the influence of protuberances on the distribution of suction surface pressure coefficient of biomimetic blades is the direct reason for the change in blade performance. The formation of stall vortices closer to the leading edge due to protuberances is an indirect reason for the improvement in sectional performance. Through the analysis of the formation mechanism, it is concluded that the flow-induced vortices induced by leading-edge protuberances are the fundamental reason for the change in sectional performance. This study reveals the coupling effect of discontinuous protuberances and protuberances wavelength on blades, providing a theoretical basis for guiding the design of biomimetic vertical axis wind turbine blades.