Experiments on Interaction between Six Vertical-Axis Wind Turbines in Pairs or Trios

The interaction between six closely placed vertical-axis wind turbines (VAWTs) in a parallel-pair arrangement (layout 1), a staggered-pair arrangement (layout 2) and a parallel-trio arrangement (layout 3) were investigated. Six miniature wind turbine models were used in the wind tunnel experiments. The rotor gap g(1) within each turbine pair or trio is set fixed values. In the layout 1, three paired turbines are in line perpendicular to the main stream. In the layout 2, two paired turbines are in line perpendicular to the main stream on a front rail and remaining paired turbines are on a rear rail. In the layout 3, two trios of turbines are in line perpendicular to the main stream. Increases in the averaged turbine power up to 106% of the single turbine power P-SI with the decrease in an inter-cluster gap g(2), have been demonstrated in the layout 1. The power of a downstream central turbine pair significantly decreases with increasing a streamwise spacing s in the layout 2. In the layout 3, the averaged turbine power reaches 0.95P(SI) for Case A. Reducing an inter-cluster interval (g(2) or s) improves a wind-farm performance in a unit footprint area in all the layouts tested.