Publications associées à Pressure head

The influence of the gas on the dynamics of cavitation bubbles

Cavitation bubbles, extensively investigated in fluid mechanics, present enduring challenges in hydraulic machinery, while holding considerable potential for practical applications in biomedicine and sonochemistry. Despite more than a century of research, ...

EPFL2023

Bottom-Pressure Development Due to an Abrupt Slope Reduction at Stepped Spillways

Anton Schleiss, Michael Pfister, José Pedro Gamito de Saldanha Calado Matos, Mohammad Javad Ostad Mirza

Fluctuating bottom-pressures on stepped chutes are relevant for the spillway design. An abrupt slope reduction causes a local alteration of the bottom-pressure development. Little information is available regarding the air–water flow properties near an abr ...

2022

Plunging Circular Jets: Experimental Characterization of Dynamic Pressures Near the Stagnation Zone

Giovanni De Cesare, Pedro Filipe De Almeida Manso, Gregoire Aurelien Marie Jamet

Spillways are a requirement for dams’ safety, mainly preventing overtopping during floods. A common spillway solution involves plunging jets, which dissipate a considerable flow energy in the plunge pool. Energy dissipation has to occur in a controlled man ...

2022

Adiabatic two-phase pressure drop of carbon dioxide in different channel orientations

Jürg Alexander Schiffmann, Rémi Revellin, David Schmid

Adiabatic pressure drop measurements of two-phase Carbon Dioxide (CO2) have been carried out in horizontal, vertical upward and downward direction with a dedicated test facility at the European Organization for Nuclear Research (CERN). A database of more t ...

2022

Experimental and Numerical Study on Scour-Protection Methods in a Stilling Basin: Case Study of Chancy-Pougny Dam

Anton Schleiss, Giovanni De Cesare, Erik Bollaert, Sabine Chamoun, Davide Wüthrich

Chancy-Pougny is a run-of-river dam on the Swiss–French border constructed in the early 1920s. Since its commissioning, the operation of the four spillway gates has been responsible for a progressive erosion of the stilling basin. The future scour potentia ...

2021

Design and fabrication of a vigorous "cavitation-on-a-chip" device with a multiple microchannel configuration

Luis Guillermo Villanueva Torrijo, Morteza Ghorbani, Merve Zuvin, Mohammad Jafarpour, Farzad Rokhsar Talabazar

Hydrodynamic cavitation is one of the major phase change phenomena and occurs with a sudden decrease in the local static pressure within a fluid. With the emergence of microelectromechanical systems (MEMS), high-speed microfluidic devices have attracted co ...

SPRINGERNATURE2021

Temporal and spatial evolution of cavitating bubbles and coherent structures in a confined submerged jet shear layer

Sebastián Camilo Leguizamón Sarmiento, Yuchuan Wang

Purpose The study aims to display the bubbles' evolution in the shear layer and their relationship with the pressure fluctuations. Furthermore, the coherent structures of the first six modes are extracted, in order to provide insight into their temporal an ...

EMERALD GROUP PUBLISHING LTD2021

An experimental study on the upper part-load elliptical vortex instability in a Francis turbine

François Avellan, Elena Vagnoni, Arthur Tristan Favrel, Andres Müller, Ali Amini

This paper presents preliminary results of an experimental study on the occurrence and development of the upper part-load instability in a reduced-scale Francis turbine. The study includes draft tube pressure measurements, high-speed flow visualization, an ...

IOP PUBLISHING LTD2021

Physical Mechanism and Flow Control of Tip Vortex Cavitation

Ali Amini

Occurrence of cavitation in hydraulic machines is a challenging issue because it is often accompanied with loss of efficiency, noise emissions, vibrations, and erosion damages. Tip vortices, in particular, are an ideal site for the development of cavitatio ...

EPFL2020

Head motion measurement and correction using FID navigators

Tobias Kober, Maryna Volodimirivna Waszak

Purpose: To develop a novel framework for rapid, intrinsic head motion measurement in MRI using FID navigators (FIDnavs) from a multichannel head coil array. ...

WILEY2019