Energy-yield-based optimization of a H-Darrieus wind turbine in skewed flow

Recent experiments and theoretical models showed that the aerodynamic performance of H-Darrieus wind turbines can even be enhanced in case of moderate skew angles, which are typical of installations in the urban environment. In this study, a design procedure oriented to the maximization of the annual energy yield in skewed flow, instead of the maximum rated power, was carried out. 14400 test cases of H-Darrieus rotors were simulated with a numerical code based on a Blade Element Momentum approach, including an in-house model to account for the skewed flow, and compared on the basis of their energy-yield capabilities for different annual wind distributions. The analysis highlighted that the optimal design configurations in skewed flow significantly differ from the corresponding ones in case of aligned flow and also that a design oriented to the maximum energy-yield in skewed flow can make H-Darrieus rotors competitive for urban installations in comparison to HAWTs.