VAN DER HORST
AIRFOIL DESIGN FOR VAWTS Including correct simulation of flow curvature Ir. Sander van der Horst, MSc Graduate Aerospace Engineering, TU Delft With the depletion of fossil fuels, increasing emissions, and the inevitability of global warming, the interest in renewable energy grows. Conventional solutions, like horizontal axis wind turbines, are reaching the limits of their capabilities. Therefore, there is renewed interest in other models, such as the Vertical Axis Wind Turbine (VAWT).
The VAWT , however, has some downsides as well. The blades pass through their own wake, it has a difficulty self-starting, and no stall mechanism so far has been invented that is safe enough. The aerodynamics asso MIGLIORE
hile there are multiple variations on the VAWT, the most viable one is the Darrieus turbine, patented in 1932 (Darrieus, 1931). This turbine operates on the principle of aerodynamic forces acting on vertically placed blades, spinning around an offset center. When enough torque is generated, power is produced. The advantages of this configuration are that it is easily scalable, will not suffer from gravitational loads and has a low center of gravity, as heavy parts like the generator are placed near the surface (Eriksson, 2008). Especially the latter characteristic make it a good contender to its horizontal axis counterpart, as a VAWT can easily be placed on floaters and anchored in the deep sea (Akimoto, 2011). For the HAWT (Horizontal Axis Wind Turbine) this is far more problematic and costly, as placing an offshore HAWT can be even more expensive than the turbine itself (MonĂŠ, 2014). Figure 1 - Virtual airfoil transformation. LEONARDO TIMES NÂ°2 2016