Large eddy simulations of turbulent flows in arrays of helical- and straight-bladed vertical axis wind turbines*

Wind turbines are often placed in large arrays with limited spacings to achieve high power density in wind energy harvesting. This limited spacing between turbines results in considerable wake-turbine interactions that can affect the performance of wind turbines. In this study, the turbulent flows in large arrays of vertical axis wind turbines (VAWTs) are modeled using large eddy simulation. The VAWT forces are applied to the flow by the actuator line method. A concurrent precursor simulation is used to generate the atmospheric boundary turbulent inflow conditions for the turbine domain simulation. Two different VAWT shapes (i.e., helical- and straight-bladed) and various streamwise and spanwise turbine spacings are considered, and their effects on the turbine array boundary layer flow are investigated systematically.