Results 21 to 30 of about 448 (209)
The numerical simulation of the rope vortex creation and the possibilities of its control
Journal of Physics: Conference Series, 2021 Abstract The rope vortex is a phenomena which can be observed in many hydraulic machines, especially turbines and pump–turbines. Its creation is based on a non uniform velocity profile characterized by high value of the circumferential component.
P Szulc +3 more
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Effect of Fins on the Internal Flow Characteristics in the Draft Tube of a Francis Turbine Model
Energies, 2020 Undesirable flow phenomena in Francis turbines are caused by pressure fluctuations induced under conditions of low flow rate; the resulting vortex ropes with precession in the draft tube (DT) can degrade performance and increase the instability of ...
Seung-Jun Kim +6 more
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Diffuser Shape Optimization Using Adjoint Solver [PDF]
MATEC Web of ConferencesShape optimization of a diffuser with vortex generator on the inlet that mimics the impeller of a Francis turbine was performed. The optimization is based on the use of the adjoint solver in ANSYS Fluent.
Pham Jakub, Rudolf Pavel
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Machines, 2022 Small vessels operating in coastal waters are susceptible to propeller failure because of the entanglement of marine debris. Secondary accidents such as the injury of divers may also occur when removing entangling material.
Antony John Nyongesa +8 more
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Coupling Mechanisms Between Vortex Rope Evolution and Cavitation Within the Draft Tube of Pump-turbines [PDF]
Journal of Applied Fluid MechanicsA technique integrating numerical simulations with experimental observations was hereby employed to elucidate the flow instability mechanisms during transient processes in pump-turbines, and a reversible pump-turbine was investigated for in-depth ...
L. Xin, Q. Li, S. Zhang
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Damping force of air acting on vibrating elevator rope
Mechanical Engineering Journal, 2021 This paper describes the vibration damping characteristics of elevator ropes acted on by air. High-rise buildings sometimes resonate during earthquakes, and the elevator ropes in the building may swing significantly as a result. The vibration analysis of
Raichi TAKUMI, Hideo UTSUNO
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Geophysical Research Letters, 2023 Two types of filamentary currents (FCs) were observed inside a magnetic flux rope at the magnetopause by the Magnetospheric Multiscale mission. The first FC is identified as an electron vortex, while the other is a reconnecting current sheet.
Shimou Wang +6 more
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POD analysis of a vortex rope with transient boundary conditions
IOP Conference Series: Earth and Environmental Science, 2019 Abstract The paper presents the results of a POD analysis of the flow in a swirl generator. The generator has two separate inlets – one straight axial inlet and one tangential inlet ended by a spiral case. This allows to set different operating points, which are in turn connected with different shapes of the vortex rope present in the ...
Ondřej Urban, Pavel Rudolf
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Measurement of Gas-Liquid Two-Phase Flow in Draft Tube
Shanghai Jiaotong Daxue xuebaoThe limitation of traditional measurement technology in gas-liquid two-phase flow measurement is broken through.The liquid velocity field and vortex rope morphology from two vertical directions were measured synchronically by using particle image ...
LI Jinfeng, CHEN Wuguang, ZHANG Zhengchuan, XU Yongliang, LI Kaiying, YIN Junlian, WANG Dezhong
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The Complex Dynamics of the Precessing Vortex Rope in a Straight Diffuser
IOP Conference Series: Earth and Environmental Science, 2016 The decelerated swirling flow in the discharge cone of Francis turbines operated at partial discharge develops a self-induced instability with a precessing helical vortex (vortex rope). In an axisymmetric geometry, this phenomenon is expected to generate asynchronous pressure fluctuations as a result of the precessing motion.
Adrian Stuparu, Romeo Susan-Resiga
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