A Theoretical and Computational Methodology to Study Vertical-axis Turbines Hydrodynamics

A research program aiming to study hydrodynamics aspects of a vertical-axis turbine is presented. The activity focuses on the development of theoretical models and computational tools to describe turbine global flowfield features and to predict performance. As a particular case, the 'Kobold' turbine developed by Ponte di Archimede S.p.A. is studied. The theoretical and computational methodology is based on a general hydrodynamics formulation valid for three-dimensional unsteady inviscid flows. Trailing vorticity dynamics and viscosity effects are taken into account through suitable modelling. The research program includes also an experimental activity primarily intended to provide data for the validation of the theoretical and computational methodology. Experiments are performed at the INSEAN model basin, where a large-scale model turbine is tested to characterize the turbine performance over a wide range of variation of operating conditions. This is a preliminary version of the paper describing the ongoing research activity. The final version will present results of turbine flow simulations and the assessment of numerical results by comparisons with experimental data from model testing.