Publications associées à Influence of Blade Aspiration on the Flow Quality of an Annular Axial Compressor Cascade

Design, computational and experimental investigation of a small-scale turbopump for organic Rankine cycle systems

Jürg Alexander Schiffmann, Sajjad Zakeralhoseini

The hydraulic design, computational analysis, and experimental investigations of a high-speed small-scale turbopump for mobile waste heat recovery applications based on organic Rankine cycle systems are presented in this paper. Such applications demand hig ...

Elsevier2023

Fiber pumps for wearable fluidic systems

Herbert Shea, Vito Cacucciolo, Michael James Henry Smith

Incorporating pressurized fluidic circuits into textiles can enable muscular support, thermoregulation, and haptic feedback in a convenient wearable form factor. However, conventional rigid pumps, with their associated noise and vibration, are unsuitable f ...

American Association for the Advancement of Science2023

Overflow pressure characterization in lined plunge pools for slab sizing

Giovanni De Cesare, Pedro Filipe De Almeida Manso, Francisca Marco Cutillas

This study presents an experimental work on dynamic pressures at the bottom of a lined plunge pool that receives overflow rectangular impinging jets and aims at improving the design criteria for pool slabs. The experiments were conducted in a fairly large ...

International Association for Hydro-Environment Engineering and Research (IAHR)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

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

Anton Schleiss, José Pedro Gamito de Saldanha Calado Matos, Michael Pfister, 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

Determination of Parameters Characteristic of Dynamic Weakening Mechanisms During Seismic Faulting in Cohesive Rocks

Marie Estelle Solange Violay, Chiara Cornelio, François Xavier Thibault Passelègue

While sliding at seismic slip-rates of ∼1 m/s, natural faults undergo an abrupt decrease of shear stress called dynamic weakening. Asperity-scale processes related to flash heating and weakening and, meso-scale (mm-cm) processes involving shear across the ...

AGU2022

In flow acoustic characterisation of a 2D active liner with local and non local strategies

Hervé Lissek, Maxime Volery, Gaël Matten

The design and the grazing flow aeroacoustical characterization of a 2D active liner based on an array of electroacoustic absorbers are presented in this paper. The strategy stands on a pressure-based, current-driven digital architecture for impedance cont ...

2022

Experimental assessment of an active (acoustic) liner prototype in an acoustic flow duct facility

Hervé Lissek, Maxime Volery, Gaël Matten

In this paper, experimental results of broadband noise reduction in an acoustic flow duct are presented. An active liner composed of an array of electroacoustic absorbers is used. The control law is based on the pressure-based, current driven digital archi ...

SPIE2021

Pressure on obstacles induced by granular snow avalanches

Michael Lukas Kyburz

The increasing population and the consequential demand for dwelling and recreation areas lead to more frequent conflicts between humans and natural hazards. In mountainous regions snow avalanches are, therefore, still a major threat to humans and infrastru ...

EPFL2021

Hydro-mechanical coupling in porous rocks: hidden dependences to the microstructure?

Lucas Xan Pimienta

While hydro-mechanical coupling in rocks is generally well understood, exotic rock poroelastic responses-such as unexpected dependence to fluid diffusion time and low skeleton moduli-have been reported. Hydro-mechanical coupling, or poroelasticity, explain ...

OXFORD UNIV PRESS2021

Benchmark study of undrained triaxial testing of Opalinus Clay shale: Results and implications for robust testing

Lyesse Laloui, Alessio Ferrari, Alberto Minardi

Triaxial testing of argillaceous rocks and shales is significantly more challenging than conventional rock mechanical testing. The challenges are mainly related to the very low permeability of these geomaterials, and their sensitivity to exposure of atmosp ...

ELSEVIER2021

Planar hydrodynamic traps and buried channels for bead and cell trapping and releasing

Philippe Renaud, Arnaud Bertsch, Daniel Migliozzi, Clémentine Sophie Sarah Lipp, Jonathan Bastien Cottet

We present a novel concept for the controlled trapping and releasing of beads and cells in a PDMS microfluidic channel without obstacles present around the particle or in the channel. The trapping principle relies on a two-level microfluidic configuration: ...

ROYAL SOC CHEMISTRY2021

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

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

Scale limitations of gas bearing supported turbocompressors for vapor compression cycles

Jürg Alexander Schiffmann

An analysis of single-stage centrifugal compressors supported on dynamic, gas lubricated bearings for driving vapor compression cycles suggests that the maximum feasible compressor power is limited, primarily by the bearing load capacity, in the range from ...

2020

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

Theoretical and Experimental Investigation of a 34 Watt Radial-Inflow Steam Turbine with Partial-Admission

Jürg Alexander Schiffmann, Jan Van Herle, Patrick Hubert Wagner

A micro steam turbine with a tip diameter of 15mm was designed and experimentally characterized. At the nominal mass flow rate and total-to-total pressure ratio of 2.3 kgh-1 and 2, respectively, the turbine yields a power of 34W and a total-to-static isent ...

2021

Theoretical and Experimental Investigation of a 34 Watt Radial-Inflow Steam Turbine with Partial-Admission

Jürg Alexander Schiffmann, Jan Van Herle, Patrick Hubert Wagner

A micro steam turbine with a tip diameter of 15 mm was designed and experimentally characterized. At the nominal mass flow rate and total-to-total pressure ratio of 2.3 kg/h and 2, respectively, the turbine yields a power of 34 W and a total-to-static isen ...

2021

Influence of Large Relative Tip Clearances for a Micro Radial Fan and Design Guidelines for Increased Efficiency

Jürg Alexander Schiffmann, Jan Van Herle, Patrick Hubert Wagner

The blade tip clearance loss was studied experimentally and numerically for a micro radial fan with a tip diameter of 19:2mm. Its relative blade tip clearance, i.e., the clearance dividedby the blade height of 1:82mm, was adjusted with different shims. The ...

2021

Fault's hydraulic diffusivity enhancement during injection induced fault reactivation: application of pore pressure diffusion inversions to laboratory injection experiments

François Xavier Thibault Passelègue

In situ observations of fluid induced fault slip reactivation, as well as the analysis of induced seismicity have demonstrated the complexity of fluid-fault interactions under geological conditions. If fluid flow commonly reactivates faults in the form of ...

OXFORD UNIV PRESS2020

Electron flux and pressure dynamic in the LHC vacuum pilot sector as a function of beam parameters and beam pipe properties

Ambrogio Fasoli, Elena Buratin, Vincent Baglin

The Large Hadron Collider (LHC) is affected by the electron cloud (EC) phenomenon that can provoke beam instabilities, detrimental heat loads and pressure increases in the vacuum system. An innovative dedicated system called vacuum pilot sector (VPS) provi ...

2020