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Concept

Effet Venturi

Publications associées (17)

Mixing and diffusion for rough shear flows

Maria Colombo, Klaus Martin Widmayer

This article addresses mixing and diffusion properties of passive scalars advected by rough (

C^\alpha

) shear flows. We show that in general, one cannot expect a rough shear flow to increase the rate of inviscid mixing to more than that of a smooth shear ...

2021

Modeling snow saltation: the effect of grain size and interparticle cohesion

Varun Sharma, Michael Lehning, Francesco Comola, Armin Sigmund, Daniela Brito Melo

This dataset includes the parallel application and the main results supporting the research article "Modeling snow saltation: the effect of grain size and interparticle cohesion" published at the Journal of Geophysical Research: Atmospheres.The code is a f ...

2021

Study of Aerodynamic Grain Entrainment in Aeolian Transport

Guang Li

Aeolian transport controls landform formations on Earth and other planets and crucially affects the atmospheric system. With elaborate wind tunnel measurements, we find that the aerodynamic entrainment rate follows a yet unreported exponential increase in ...

2020

Scanning PIV of turbulent flows over and through rough porous beds using refractive index matching

Christophe Ancey, Gauthier Paul Daniel Marie Rousseau

This paper presents image velocimetry measurements on turbulent flows adjacent to a permeable bed made of randomly packed glass particles. For measuring flow velocities inside the bed, the refractive index of the glass particles was matched with that of th ...

SPRINGER2020

Two-fluid plasma model for radial Langmuir probes as a converging nozzle with sonic choked flow, and sonic passage to supersonic flow

Ivo Furno, Alan Howling, Philippe Frédérique Bruno Guittienne

Using the Lambert function, Guittienne et al. [Phys. Plasmas 25, 093519 (2018)] derived two-fluid solutions for radial Langmuir probes in collisionless and isothermal plasma. In this Brief Communication, we point out the close analogy with classical compre ...

American Institute of Physics (AIP)2019

Effect of spilling from adjacent orifices on the velocity field and pressures in front of needle stop-logs

Giovanni De Cesare, Azin Amini, Ivan Stojnic, Cédric Bron

In this study, the effect of spilling from neighboring sluice gates on stop-logs was experimentally investigated on a 1:65 physical scale model comprised of a double arch dam, a reservoir area, six spillway orifices and two stop-logs. Two types of measurem ...

2018

Effects of Lateral and Vertical Constrictions on Flow in Rough Steep Channels with Bedload

Anton Schleiss, Mário Jorge Rodrigues Pereira Da Franca, Sebastian Schwindt

Two-phase flows occurring at flow constrictions such as bridges or open sediment check dams are complex, especially for steep rivers with bedload transport. Dangerous bedload deposition and backwater effects may occur in steep mountain rivers at bridges. I ...

Asce-Amer Soc Civil Engineers2017

Bulk velocity measurements by video analysis of dye tracer in a macro-rough channel

Anton Schleiss, Mário Jorge Rodrigues Pereira Da Franca, Tamara Ghilardi

Steep mountain rivers have hydraulic and morphodynamic characteristics that hinder velocity measurements. The high spatial variability of hydraulic parameters, such as water depth (WD), river width and flow velocity, makes the choice of a representative cr ...

IOP Publishing2014

A theory for the streamwise turbulent fluctuations in high Reynolds number pipe flow

A new theory for the streamwise turbulent fluctuations in fully developed pipe flow is proposed. The theory extends the similarities between the mean flow and the streamwise turbulence fluctuations, as observed in experimental high Reynolds number data, to ...

Cambridge University Press2012

Control of axisymmetric vortex breakdown in a constricted pipe: Nonlinear steady states and weakly nonlinear asymptotic expansions

François Gallaire, Philippe Meliga

The present paper investigates numerically and theoretically the axisymmetric vortex breakdown occurring in a constricted pipe of infinite extension, i.e., the transition from a smooth columnar state to a breakdown state exhibiting a recirculation bubble. ...

2011

Reduced basis approximation and error bounds for potential flows in parametrized geometries

Gianluigi Rozza

In this paper we consider (hierarchical, Lagrange) reduced basis approximation and a posteriori error estimation for potential flows in affinely parametrized geometries. We review the essential ingredients: i) a Galerkin projection onto a low dimensional s ...

2011

Alternative depth-averaged models for gravity currents and free shear flows

Anton Schleiss

Two approaches have traditionally been used to describe the widening rate of jets and plumes: the diffusion concept of Prandtl, and the entrainment principle of Morton, Taylor and Turner. The entrainment concept is based on depth-averaged flow scales, and ...

Springer Verlag2010

Numerical simulation of fluid added mass effect on a francis turbine runner

François Avellan, Mohamed Farhat

In this paper, a numerical simulation to analyze the influence of the surrounding water in a turbine runner has been carried out using finite element method (FEM). First, the sensitivity of the FEM model on the element shape and mesh density has been analy ...

2007

Experimental Study and Numerical Simulation of the Flindt Draft Tube Rotating Vortex

François Avellan, Monica Iliescu

The dynamics of the rotating vortex taking place in the discharge ring of a Francis turbine for partial flow rate operating conditions and cavitation free conditions is studied by carrying out both experimental flow survey and numerical simulations. 2D las ...

2007

Microscale total analysis system

Hubert Girault

The invention relates to an apparatus for performing chemical assays in an aqueous medium. The apparatus contains a reaction chamber(s) and a liquid in-flow channel connected to each chamber. The flow of liquid through the fluid in-flow channel to the reac ...

2005

A field study of turbulent flows in shallow gravel-bed rivers

Mário Jorge Rodrigues Pereira Da Franca

The study of turbulent flows has always been a challenge for scientists. Turbulent flows are common in nature and have an important role in several geophysical processes related to a variety of phenomena such as river morphology, landscape modeling, atmosp ...

EPFL2005

High velocity aerated flow on stepped chutes with macro-roughness elements

Stéphanie Joëlle André

Uncontrolled overtopping during flood events can endanger embankment dams. Erosion of the downstream slope and scouring of its base caused by the high velocity and energy of the overflow can indeed lead to breach formation until complete failure. In this c ...

EPFL2004

Publications associées (17)

Mixing and diffusion for rough shear flows

Maria Colombo, Klaus Martin Widmayer

This article addresses mixing and diffusion properties of passive scalars advected by rough (

C^\alpha

) shear flows. We show that in general, one cannot expect a rough shear flow to increase the rate of inviscid mixing to more than that of a smooth shear ...

2021

Two-fluid plasma model for radial Langmuir probes as a converging nozzle with sonic choked flow, and sonic passage to supersonic flow

Ivo Furno, Alan Howling, Philippe Frédérique Bruno Guittienne

American Institute of Physics (AIP)2019

Control of axisymmetric vortex breakdown in a constricted pipe: Nonlinear steady states and weakly nonlinear asymptotic expansions

François Gallaire, Philippe Meliga

2011