Vertical Axis Wind Turbine
Vertical-axis wind turbines (VAWTs) are a type of wind turbine where the main rotor shaft is set vertically and the main components are located at the base of the turbine. Among the advantages of this arrangement are that generators and gearboxes can be placed close to the ground, which makes these components easier to service and repair, and that VAWTs do not need to be pointed into the wind. Major drawbacks for the early designs (Savonius, Darrieus and giromill) included the pulsatory torque that can be produced during each revolution and the huge bending moments on the blades. Later designs solved the torque issue by using the helical twist of the blades almost similar to Gorlov's water turbines.
A VAWT tipped sideways, with the axis perpendicular to the wind streamlines, functions similarly. A more general term that includes this option is "transverse axis wind turbine". For example, the original Darrieus patent, includes both options.
Drag-type VAWTs, such as the Savonius rotor, typically operate at lower tipspeed ratios than lift-based VAWTs such as Darrieus rotors and cycloturbines.
A unique, mixed Darrieus - Savonius VAWT type has recently been developed and patented. The main benefits obtained are improved performance at lower wind speeds and a lower r.p.m. regime at higher wind speeds resulting in a silent turbine suitable for residential environments.
Read more about Vertical Axis Wind Turbine: General Aerodynamics, Advantages of Vertical Axis Wind Turbines, Disadvantages of Vertical Axis Wind Turbines
Famous quotes containing the words vertical, axis and/or wind:
“In bourgeois society, the French and the industrial revolution transformed the authorization of political space. The political revolution put an end to the formalized hierarchy of the ancien regimé.... Concurrently, the industrial revolution subverted the social hierarchy upon which the old political space was based. It transformed the experience of society from one of vertical hierarchy to one of horizontal class stratification.”
—Donald M. Lowe, U.S. historian, educator. History of Bourgeois Perception, ch. 4, University of Chicago Press (1982)
“I make this direct statement to the American people that there is far less chance of the United States getting into war, if we do all we can now to support the nations defending themselves against attack by the Axis than if we acquiesce in their defeat, submit tamely to an Axis victory, and wait our turn to be the object of attack in another war later on.”
—Franklin D. Roosevelt (1882–1945)
“. . . A widow bird sat mourning for her love
Upon a wintry bough;
The frozen wind crept on above,
The freezing stream below.”
—Percy Bysshe Shelley (1792–1822)