Etude de l'influence des instationnarités des écoulements sur le développement de la cavitation
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The present work deals with time dependent phenomena, which develop in turbines and pump turbines of Francis type. These phenomena may cause serious damages to hydropower plant. The overall objective of this study is to bring a better understanding of two ...
Placed in a fluid stream, solid bodies can exhibit a separated flow that extends to their wake. The detachment of the boundary layer on both upper and lower surfaces forms two shear layers which generate above a critical value of Reynolds number a periodic ...
At part load operation of Francis turbine, the swirl in the draft tube leads to flow instability known as vortex breakdown. This flow instability can interact with the rest of the hydraulic circuit through axially propagating plane-waves. Moreover, at low ...
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Centrifugal pumps are required to sustain a stable operation of the system they support under all operating conditions. Minor modifications of the surfaces defining the pump's water passage can influence the tendency to unstable system operation significan ...
The flow in the draft tube cone of Francis turbines operated at partial discharge is a complex hydrodynamic phenomenon where an incoming steady axisymmetric swirling flow evolves into a three-dimensional unsteady flow field with precessing helical vortex ( ...
International Association For Hydraulic Research2008
An experimental research of flow on different systems of stepped overlays for 18.6 degrees and 30 degrees slopes was conducted. In addition to define flow characteristics (Part I), the study highlighted the existence of an homogeneous aerated flow in which ...
Hydraulic power is a renewable energy with a very advantageous price, and its flexibility of use coupled with its storage possibilities easily enables to meet the peak demand. Refurbishment of old hydraulic power plants is an important topical issue and th ...
The currents in the lowest few millimeters of the bottom boundary layer of lakes are highly important for the dissipation of kinetic energy and for chemical processes such as oxygen transfer into the sediment. So far, no high-resolution flow velocity profi ...
All hydraulic turbines containing a casing with stay vanes face the potential dynamic problem of stay vane von Kármán vortex shedding. For hydraulic efficiency purposes the stay vanes tend to be relatively slender in the direction normal to the flow thus b ...
