Geometrical Parameters Influencing the Aerodynamic Efficiency of a Small Scale Self Pitch High Solidity VAWT

Abstract

In this paper, four key design parameters with a strong influence on the performance of a highsolidity variable pitch vertical axis wind turbine (VAWT) operating at low tipspeedratio (TSR) are addressed. To this aim, a numerical approach, based on a finitevolume discretization of twodimensional (2D) unsteady Reynoldsaveraged Navier–Stokes (URANS) equations, on a multiple sliding mesh, is proposed and validated against experimental data. The selfpitch VAWT design is based on a straightblade Darrieus wind turbine with blades that are allowed to pitch around a feathering axis, which is also parallel to the axis of rotation. The pitch angle amplitude and periodic variation are dynamically controlled by a fourbar linkage system. We only consider the efficiency at low and intermediate TSR; therefore, the pitch amplitude is chosen to be a sinusoidal function with a considerable amplitude. The results of this parametric analysis will contribute to define the guidelines for building a fullsize prototype of a smallscale wind turbine of increased efficiency.