Concept

Précession

Publications associées (52)

Current Control Strategy for Dynamic Winding Reconfiguration of Slotless Brushless DC Motors

Yves Perriard, Douglas Martins Araujo, Florian Louis Copt

Depending on the winding configuration, the intrinsic characteristic of a motor differs. By reconfiguring the winding, it becomes possible to increase the torque–speed limitation of a motor. Current proposed methodologies for dynamically reconfiguring the ...

2019

New insight in Francis turbine cavitation vortex rope: role of the runner outlet flow swirl number

François Avellan, Christophe Nicolet, Arthur Tristan Favrel, Christian Landry, Andres Müller, Joao Gomes Pereira Junior

At part load operation, Francis turbines experience the development of a cavitation vortex rope in the draft tube, whose precession acts as a pressure excitation source. In case of resonance, the resulting pressure pulsations lead to unacceptable torque an ...

2018

Dynamics of the precessing vortex rope and its interaction with the system at Francis turbines part load operating conditions

François Avellan, Arthur Tristan Favrel, Christian Landry, Andres Müller, Keita Yamamoto, Joao Gomes Pereira Junior

At part load conditions, Francis turbines experience the formation of a cavitation vortex rope at the runner outlet whose precession acts as a pressure excitation source for the hydraulic circuit. This can lead to hydro-acoustic resonances characterized by ...

2017

Full-Scale Cyclic Testing of Deep Slender Wide-Flange Steel Beam-Columns under Unidirectional and Bidirectional Lateral Drift Demands

Dimitrios Lignos, Ahmed Mohamed Ahmed Elkady

Deep and slender wide-flange steel beam-columns are commonly used in steel special moment frames (SMFs) in North America. These sections provide large moment-of-inertia required to satisfy the design code’s drift limits while keeping the column steel weigh ...

International Association of Earthquake Engineering2017

Space and time reconstruction of the precessing vortex core in Francis turbine draft tube by 2D-PIV

François Avellan, Arthur Tristan Favrel, Christian Landry, Andres Müller, Keita Yamamoto

Francis turbines operating at part load conditions experience the development of a high swirling flow at the runner outlet, giving rise to the development of a cavitation precessing vortex rope in the draft tube. The latter acts as an excitation source for ...

International Association For Hydraulic Research2016

Low frequency terahertz-induced demagnetization in ferromagnetic nickel

Christoph Peter Hauri, Mostafa Shalaby

A laser stimulus at terahertz (THz) frequency is expected to offer superior control over magnetization dynamics compared to an optical pulse, where ultrafast demagnetization is mediated by heat deposition. As a THz field cycle occurs on a timescale similar ...

Amer Inst Physics2016

Current-Induced Spin Polarization in Topological Insulator-Graphene Heterostructures

Klaus Kern, Marko Burghard, Alexander Ronald Hoyer, Kristina Vaklinova

Further development of the field of all-electric spintronics requires the successful integration of spin transport channels with spin injector/generator elements. While with the advent of graphene and related 2D materials high performance spin channel mate ...

Amer Chemical Soc2016

Linear response to a heat-driven spin torque

Jean-Philippe Ansermet, Haiming Yu, Francesco Antonio Vetrò, Christian Caspers, Lucas Fitoussi

The existence of a heat-driven spin torque is demonstrated using Co/Cu/Co spin valves embedded in metallic nanowires. Heat currents flowing in one direction or its opposite were obtained by heating optically one end or the other of the nanowires. The spin ...

Amer Inst Physics2015

Hydro-acoustic resonance behavior in presence of a precessing vortex rope: observation of a lock-in phenomenon at part load Francis turbine operation

François Avellan, Arthur Tristan Favrel, Christian Landry, Andres Müller, Keita Yamamoto

Francis turbines operating at part load condition experience the development of a cavitating helical vortex rope in the draft tube cone at the runner outlet. The precession movement of this vortex rope induces local convective pressure fluctuations and a s ...

IOP science2014

Hydro-acoustic resonance behavior in presence of a precessing vortex rope: observation of a lock-in phenomenon at part load Francis turbine operation

François Avellan, Arthur Tristan Favrel, Christian Landry, Andres Müller, Keita Yamamoto

Iop Publishing Ltd2014

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