Parametric study of the dual vertical axis wind turbine using CFD

The Dual Vertical Axis Wind Turbine (D-VAWT) is an innovative turbine proposed to improve the aerodynamic efficiency of small Vertical Axis Wind Turbines (VAWTs). The D-VAWT has two axes, allowing the blades to move in an oval shaped path to extend the region of maximum power generation of a typical VAWT. The aim of this paper is to perform a parametric study on the D-VAWT variables as a previous investigation aimed only to prove its concept. The current study is performed through 2D unsteady simulations using computational fluid dynamics. Advanced moving mesh techniques are used to prescribe the motion of the blades, combining the sliding and dynamic mesh techniques as well as re-meshing for multi-blade simulations. A turbine with a single blade is first investigated to determine the relation between the tip speed ratio (TSR) and power coefficient. The investigation continues with the study of the turbine sensitivity to different incoming wind angles, turbine axes spacing, number of blades, airfoil profile and blade mounting point. It was found that the D-VAWT has a low sensitivity to TSR, allowing the turbine to operate efficiently for a wide range of TSRs.