Abstract
The effective shape of surrounding structures was investigated to improve the power output of
vertical axis wind turbines through wind tunnel experiments. A VAWT equipped with a pair of vertical flat
plates in the upstream demonstrated power augmentation by a factor of 2.4 compared to the VAWT
without plates. The pair of plates could accelerate the gap flow in the downstream wind, and also could
reduce a drag force to a blade of a VAWT toward upstream. We proposed a recommended shape of the
structures which consist of flat panels in the upstream.
