Abstract
The aim of this investigation is to develop an open cross-flow type runner utilizing small waterfall which has extreme
low head. Two type runners, impulse type and cross-flow type, were compared with each performance. Especially we
focused on the difference of flow patterns through the runner. As a result, the cross-flow runner is superior to the impulse
type runner because that stagnation flow in the cross-flow runner is not occurred. Power coefficient of the cross-flow type
indicates higher value in wider range of tip speed ratio than that of the impulse type. The maximum power coefficient of the
cross-flow runner reached at 0.74.
