START-UP MECHANISM OF A VAWT CONSISTING OF THREE QUARTER CIRCULAR-ARC BLADES ATTACHED TO A CYLINDRICAL CORE

Abstract

The aim of this paper is to computationally investigate unsteady flow around an autorotating drag-type vertical-axis wind turbine which consists of three quarter circular-arc blades attached to a cylindrical core. Three values of the attachment angle of the circular-arc blades are selected as alpha (20 degree, 40 degree and 45 degree). The vortex particle method is adopted as a computational procedure. As a result, autorotation of the rotor can be simulated successfully, and it can be found that the rotor oppositely rotates between alpha less than 45 degree(forward) and alpha equal/more 45 degree(backward). In particular, the initial vortex shedding from the blades can be found to play an important role for starting up.