A straight-bladed vertical axis wind turbine with a directed guide vane row has been proposed and tested by the authors, in order to overcome the disadvantages of vertical axis wind turbine. However, field test of the proposed wind turbine has not been carried out so far. In the study, performance of straight-bladed vertical axis wind turbine with a directed guide vane row was investigated experimentally in field. The tested wind turbine has some straight rotor blades with a profile of NACA0018, a chord length of 100 mm, a diameter of 1.0 m and a height of 1.5 m. The rated power is 500W.
Floating offshore wind farms are being considered for Japanese waters. In such case, in order to control behavior of the float, it is very important to use a vertical axis wind turbine which has low center of gravity. This turbine consists of several aerofoil vertically mounted on a rotating shaft (Fig. 1). Although the turbine needs a bearing at the top of the structure and has complicated aerodynamic interaction between the downwind blades and the wakes of the upwind blades, it has some advantages in comparison with a horizontal axis wind turbine (HAWT):
The center of gravity is relatively lower because the generator and gearbox can be placed on the ground.
A yaw mechanism to turn the rotor against the wind is not necessary for the turbine system.
On the other hand, however, there are substantial drawbacks of S-VAWT. That is, the power coefficient and self-starting characteristic of S-VAWT are less than those of HAWT. The guide vane which consists of arc plate rotates around the rotor and is directed to the wind by aerodynamic force generated by tail vane, so as to put the guide vane in upstream of the rotor.
