In this study, CFD simulation of a VAWT coupled with a specially-designed wind booster is
performed in order to analyze what effects on air streams that lead to an increase in the overall angul arspeed of a VAWT at low wind speed conditions of 1 m/s to 8 m/s. Actually, there is another typical method, which is able to increase power output of VAWT by enlarging size of turbine. However, the reasons to increase wind speed are: 1.) The relationship between wind speed and wind power is “power is proportional to wind speed3”; therefore, increasing wind speed can greatly multiply power output of a VAWT compared with an increase in size of a turbine. It can be expressed as: