The influence of support arms on the performance of vertical axis wind turbines

Abstract

The vertical axis wind turbines (VAWT) are being used for small to medium-scale energy extraction, primarily for off grid applications. Several investigations on the VAWTs dealing with turbine blade optimisation and applications are reported. However, most of the literature have often neglected the effect of turbine arms during the numerical analysis, except a few. This study concerns the aerodynamic characteristics of support arm in 3D numerical predictions on the performance of a two-bladed VAWT with dual support arm configuration. Results with arms were compared against an ideal turbine with no support arms, which was set as the baseline. The numerical study with respect to power coefficients as well as characterisation of the turbine flow physics during turbine operations were conducted. The difference increased as the TSR value increased. The power coefficient comparisons saw a significant reduction in the predicted power coefficient due to the parasitic effect of the turbine arms. Both velocity and pressure contours showed that the turbine support arms' added consideration results in a much more turbulent flow around the turbine.