Background: Electricity generation from wind turbines is an established energy sector undergoing rapid growth in the US and worldwide. The US installed wind power capacity at the end of 2007 was 16596 MW. This represents more than a three-fold increase in wind power capacity over a five year period and the aggressive capacity growth is predicted to continue. The majority of the installed wind turbines are a horizontal axis design resembling an adaption of the propeller. Although horizontal axis wind turbines are well-established they are complex and costly to transport and install. The alternate vertical axis wind turbine (VAWT) designs have had limited commercial success to date despite the advantage that they can collect wind from all directions. The classic lift-based VAWT design originates from the 1920's and the creator George Darrieus. The Darrieus-type VAWT uses guy cables to keep the turbine erect which can cause wear of the bottom bearing. Technology Description: Prof. Wygnanski at The University of Arizona Department of Aerospace and Mechanical Engineering is developing an improved design for a lift-type VAWT. This improved VAWT design incorporates features that should translate into a wider operational envelope for the turbine while also minimizing wear of the bottom bearing. The anticipated improved operational envelope is a combination of the new VAWT design and the use of active flow control to delay the occurrence of dynamic-stall experienced with the Darrieus VAWT. A proof-of-concept demonstration is planned. Applications: Electricity generation
Vertical Axis Wind Turbine with active flow control which delays the occurrence of dynamic-stall widens the operational envelope and increases the performance of the vertical axis wind turbine.