K
Keita Yamamoto
Researcher at École Polytechnique Fédérale de Lausanne
Publications - 24
Citations - 512
Keita Yamamoto is an academic researcher from École Polytechnique Fédérale de Lausanne. The author has contributed to research in topics: Francis turbine & Draft tube. The author has an hindex of 12, co-authored 22 publications receiving 401 citations. Previous affiliations of Keita Yamamoto include Osaka University.
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Study of the vortex-induced pressure excitation source in a Francis turbine draft tube by particle image velocimetry
TL;DR: In this paper, a two-component particle image velocimetry system is used to investigate the flow field at the runner outlet of a reduced-scale physical model of a Francis turbine.
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LDV survey of cavitation and resonance effect on the precessing vortex rope dynamics in the draft tube of Francis turbines
TL;DR: In this paper, the impact of cavitation and hydro-acoustic resonance on both axial and tangential velocity fluctuations in terms of amplitude and phase shift is highlighted for the first time, suggesting that the synchronous axial velocity fluctuations are surprisingly negligible compared to the velocity fluctuations induced by the vortex precession.
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Experimental evidence of inter-blade cavitation vortex development in Francis turbines at deep part load condition
TL;DR: In this paper, the authors introduced a novel visualization technique with instrumented guide vanes embedding the visualization devices, providing unprecedented views on the inter-blade cavitation vortex, which is a typical cavitation phenomenon observed at deep part load operation.
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Measurement of the Self-Oscillating Vortex Rope Dynamics for Hydroacoustic Stability Analysis
Andres Müller,Keita Yamamoto,Sébastien Alligné,Koichi Yonezawa,Yoshinobu Tsujimoto,François Avellan +5 more
TL;DR: In this paper, the cavitation volume is calculated by integrating the corresponding discharge difference over time, where the discharge difference between two points located upstream and downstream of the cavity is used to calculate the local cross-section areas of a cavitation.
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On the physical mechanisms governing self-excited pressure surge in Francis turbines
TL;DR: In this paper, the authors investigated the relationship between the self-excited pressure and vortex rope oscillation and the cyclic appearance of the blade cavitation in a reduced scale model of a Francis turbine.