Aerodinamic interference between two Darrieus wind turbine / P. R. Schatzle, P. C. Klimas and H. R. Spahr

The effect of aerodynamic interference on the performnce of two curved bladed Darrieus-type vertical axis wind turbines has been calculated using a vortex/lifting line aerodynamic model. The turbines have a tower-to-tower separation distance of 1.5 turbine iameters, with the line of turbine centers varying with respect to the ambient wind direction. The effects of freestream turbulence werw neglected. For the cases examined, the calculations showed that the downwind turbine power decrement (1) was significant only when the line of turbine centers was coincident with the ambient wind direction, (2) increased with increasing tipspeed ratio, and (3) is due more to induced flow angularities downstream thn to speed deficits near the downstream turbine.