Wind Turbine Aerodynamics

Wind Turbine Aerodynamics

The primary application of wind turbines is to extract energy from the wind. Hence, the aerodynamics is a very important aspect of wind turbines. Like many machines, there are many different types all based on different energy extraction concepts. Similarly, the aerodynamics of one wind turbine to the next can be very different.

Overall the details of the aerodynamics depend very much on the topology. There are still some fundamental concepts that apply to all turbines. Every topology has a maximum power for a given flow, and some topologies are better than others. The method used to extract power has a strong influence on this. In general all turbines can be grouped as being lift based, or drag based with the former being more efficient. The difference between these groups is the aerodynamic force that is used to extract the energy.

The most common topology is the Horizontal-axis wind turbine (HAWT). It is a lift based wind turbine with very good performance, accordingly it is a popular for commercial applications and much research has been applied to this turbine. In the latter part of the 20th century the Darrieus wind turbine was another popular lift based alternative but is rarely used today. The Savonius wind turbine is the most common drag type turbine, despite its low efficiency it is used because it is robust and simple to build and maintain.