Computational aerodynamic optimisation of vertical axis wind turbine blades

•CFD used for novel vertical axis wind turbine design.•A new parameterisation scheme developed•Design of experiments and Nelder–Mead simplex optimisation used.•New blade design developed – currently being tested.

The approach and results of a parametric aerodynamic optimisation study is presented to develop the blade design for a novel implementation of a vertical axis wind turbine. It was applied to optimise the two-dimensional cross-sectional geometry of the blades comprising the turbine. Unsteady viscous computational fluid dynamic simulations were used to evaluate blade performance. To compare geometries, the non-dimensional coefficient of power was used as a fitness function. Moving meshes were used to study the transient nature of the physical process. A new parameterisation approach using circular arcs has been developed for the blade cross sections. The optimisation process was conducted in two stages: firstly a design of experiments based response surface fitting was used to explore the parametric design space followed by the use of a Nelder–Mead simplex gradient-based optimisation procedure. The outcome of the optimisation study is a new blade design that is currently being tested in full-scale concept trials by a partnering wind energy company.