Paper Title
Numerical Study to Improve The Performance of A Vertical Axis Wind Turbine By Applying A Wind Tower

Abstract
Since a wind tower can increase the wind velocity as well as adjust the wind direction, the performance of a vertical axis wind turbine (VAWT) can be augmented. However, it is very important to correctly determine the configuration of the wind tower because the wind tower can also interrupt the wind flow towards the wind turbine. Hence, a numerical analysis was conducted to investigate an effective wind tower configuration using computational fluid dynamics (CFD). For practical reasons, a numerical algorithm using a reduced computational domain was applied because the full three-dimensional CFD required huge amounts of computation time for a transient analysis. This method was validated using experiment results, and was then applied to the computation of a wind tower with an installed VAWT. Three wind tower design parameters were chosen for investigation, the inner radius, outer radius, and relative angle of the guide wall. When these parameters were correctly determined, the wind tower always increased the performance of the VAWT in an omnidirectional wind. In addition, the maximum power coefficient was increased up to more than 67% compared with that without the wind tower. Keywords- Wind turbine, Vertical Axis Wind Turbine, CFD, Performance Enhancement, Wind Tower.