Wake Formations Behind a Multi-element Vertical Axis Wind Turbine

Vertical axis wind turbines (VAWT) are a potential energy solution for more urban environments because of their minimal size and noise pollution. While single airfoil VAWTs have been thoroughly studied, by introducing a multi-element airfoil VAWT there is a wide range of variables that are subject to change. Using particle image velocimetry (PIV) we aim to analyze the wake structures behind a scaled multi-element VAWT in a wind tunnel. Constant temperature anemometry along with the PIV results temporally resolve wake regions of interest chosen from the PIV analysis. A comparison will be made of the wake structure behind single airfoil and multi-element airfoil VAWTS. The multi-element airfoil VAWT produces significantly more vortex structures and patterns in the wake. In addition, multi-element airfoil VAWTs behave more like a solid cylinder due to the greater solidity compared to a single airfoil VAWT. Furthermore, the tip-to-speed ratio (TSR) is compared in two values to expand on existing research of the importance of TSR on single airfoil VAWT’s.