Wake Formations of a Multi-element Vertical Axis Wind Turbine

Vertical axis wind turbines(VAWTs) are used as a renewable energy source in urban environments and in between horizontal axis wind turbines for their small stature, low noise pollution and small amount of wind needed to create energy. We have done single element VAWTs in the past which gave great insights into this. Our current aim is looking at complicated blade geometries to see how different blade shapes and orientations affect the wake. Using PIV in our wind tunnel we have shown interesting, complicated wake formations when adding a second set of blades at a different diameter changes the wake structure behind the VAWT. The multi-element VAWT re-shapes the wake due to having two separate tip-speed ratios, inside diameter and outside diameter.