Abstract
The aim of this investigation is to develop an open type cross-flow runner for eco-friendly pico-hydraulic turbine utilizing an extra-low head waterfall. We use a flow direction control method with a convex shaped channel to adjust precisely the position of the runner every time when flow rate changes. But this method has disadvantage that water surface deforms and fluctuates. These water fluctuation disturbs high performance. So, we investigated experimentally the characteristics of water flowing over convex surface. As a result, there are three patterns in the growing rate of waving defer motion of the water.
