Results 11 to 20 of about 18,405 (147)

Effects from dayside magnetosphere to distant tail unleashed by a bifurcated, non-reconnecting interplanetary current sheet

Frontiers in Physics, 2022
Global magnetospheric effects resulting from the passage at Earth of large-scale structures have been well studied. The effects of common and short-term features, such as discontinuities and current sheets (CSs), have not been studied in the same depth ...
C. J. Farrugia, N. Lugaz, S. Wing, L. B. Wilson, D. J. Sibeck, S. W. H. Cowley, R. B. Torbert, B. J. Vasquez, J. Berchem   +8 more
doaj   +1 more source

Numerical Simulation of the Flow in a Kaplan Turbine Model during Transient Operation from the Best Efficiency Point to Part Load

Energies, 2020
The aim of this study is to develop a reliable numerical model that provides additional information to experimental measurements and contributes to a better exploitation of hydraulic turbines during transient operation.
Raluca G. Iovănel, Georgiana Dunca, Diana M. Bucur, Michel J. Cervantes   +3 more
doaj   +1 more source

Research on the Three-dimensional Transient Characteristics of the Hydraulic System during Load Rejection with Combined Regulation of Ball Valve and Guide Vanes in the Entire Hydraulic Passage of the Pumped Storage Power Stations [PDF]

Journal of Applied Fluid Mechanics
The complex transient flow field in the entire hydraulic system of a large pump turbine under load rejection conditions, involving the simultaneous closing of the ball valve and guide vanes, is comprehensively investigated using the Re-Normalization ...
X. Li, X. Tang, Q. Ren, Q. Liu, H. An
doaj   +1 more source

Formation of Rotating Vortex Rope in the Francis-99 Draft Tube

IOP Conference Series: Earth and Environment, 2019
The aim of this research is to understand the mechanism(s) of RVR formation during the changes in operating condition from the Best Efficiency Point (BEP) to Part Load (PL).
N. Sotoudeh, R. Maddahian, M. Cervantes
semanticscholar   +1 more source

Connection between inlet velocity field and diffuser flow instability [PDF]

Applied and Computational Mechanics, 2009
Simulations of the flow in a straight diffuser were carried out for different inlet velocity profiles equivalent to the real turbine operating points. Frequencies and magnitudes of pressure pulsations of the rotating vortex rope were recorded.
Rudolf P.
doaj  

Flow Field Analysis of Francis Turbine Draft Tube using POD at Design and Part Load Operating Conditions [PDF]

Journal of Applied Fluid Mechanics
The hydraulic turbines, especially Francis turbines, frequently run at part load (PL) conditions to meet the dynamic energy needs. The flow field at the runner exit changes significantly with a change in the operating point.
S. Kumar, M. J. Cervantes, B. K. Gandhi
doaj   +1 more source

Enhancing Bulb Turbine Performance Assessing Air Injection for Vibration Mitigation and Hydrofoil Cavitation [PDF]

Journal of Applied Fluid Mechanics
Small hydro technology is playing a crucial role in advancing sustainable, clean energy policies as part of the global hydro development strategy. Its contribution to social and economic development is becoming more prominent, particularly in ensuring ...
S. Praveen, S. Marimuthu, B. Alqahtani, G. Bharathiraja, G. Gokilakrishnan   +4 more
doaj   +1 more source

Power Swing Generated in Francis Turbines by Part Load and Overload Instabilities

Energies, 2017
Hydropower plays a key role in the actual energy market due to its fast response and regulation capacity. In that way, hydraulic turbines are increasingly demanded to work at off-design conditions, where complex flow patterns and cavitation appear ...
David Valentín, Alexandre Presas, Eduard Egusquiza, Carme Valero, Mònica Egusquiza, Matias Bossio   +5 more
doaj   +1 more source

A Novel Passive Method to Control the Swirling Flow with Vortex Rope from the Conical Diffuser of Hydraulic Turbines with Fixed Blades

Applied Sciences, 2019
In this paper, we introduce a novel passive control method to mitigate the unsteadiness effects associated to the swirling flows with self-induced instabilities. The control method involves a progressive throttling cross-section flow at the outlet of the
C. Tănasă, A. Bosioc, S. Muntean, R. Susan-Resiga   +3 more
semanticscholar   +1 more source

Vortex structure identification for supersonic flows

Journal of Physics: Conference Series, 2020
This work is devoted to the application of vortex structure identification methods for two counter-rotating wingtip vortices in a supersonic flow.
V. E. Borisov, A. A. Davydov, T. Konstantinovskaya, A. E. Lutsky   +3 more
semanticscholar   +1 more source