1. Laboratory for Hydraulic Machines, Ecole Polytechnique Fédérale de Lausanne, Avenue de Cour 33bis, 1007 Lausanne, Switzerland
2. Graduate School of Engineering, Tohoku University, 6–6–01 Aoba, Aramaki, Aoba, Sendai, Miyagi 980–8579, Japan
3. Institute of Fluid Science, Tohoku University, 2–1–1 Katahira, Aoba, Sendai, Miyagi 980–8577, Japan
4. Department of Electronic Engineering, Tohoku University, 6–6–05 Aoba, Aramaki, Aoba, Sendai, Miyagi 980–8579, Japan