Publications related to Similitude

A Bayesian data assimilation framework for lake 3D hydrodynamic models with a physics-preserving particle filtering method using SPUX-MITgcm v1

Damien Bouffard, Camille Roland Marie Minaudo, Cintia Luz Ramon Casanas, Firat Ozdemir

We present a Bayesian inference for a three-dimensional hydrodynamic model of Lake Geneva with stochastic weather forcing and high-frequency observational datasets. This is achieved by coupling a Bayesian inference package, SPUX, with a hydrodynamics packa ...

COPERNICUS GESELLSCHAFT MBH2022

CO2-Driven diffusiophoresis and water cleaning: similarity solutions for predicting the exclusion zone in a channel flow

Mrudhula Baskaran

We investigate experimentally and theoretically diffusiophoretic separation of negatively charged particles in a rectangular channel flow, driven by CO2 dissolution from one side-wall. Since the negatively charged particles create an exclusion zone near th ...

ROYAL SOC CHEMISTRY2021

A plane‐strain hydraulic fracture driven by a shear‐thinning Carreau fluid

Brice Tanguy Alphonse Lecampion, Lucas Pereira

We study the propagation of a plane‐strain hydraulic fracture driven by a shear thinning fluid following a Carreau rheology. We restrict to the impermeable medium case and quantify in details the impact on fracture growth of the shear‐thinning properties o ...

2021

Swirl number based transposition of flow-induced mechanical stresses from reduced scale to full-size Francis turbine runners

François Avellan, Christian Landry, Arthur Tristan Favrel, Keita Yamamoto, Joao Gomes Pereira Junior

At part load conditions, Francis turbines are subject to the emergence of a hydrodynamic instability in their draft tube, referred to as precessing vortex rope. It induces pressure pulsations in the water passages at the precession frequency of the vortex, ...

2020

Shape optimisation of technical devices via gradient descent using convolutional neural network proxies

Pascal Fua, François Fleuret, Pierre Bruno Baqué

The present invention generally relates to a method, a system and a computer program for shape optimisation of a technical device adapted to be exposed to a fluid flowing around a contour of said device with respect to its fluid dynamic parameters. In orde ...

2019

Experiments versus theory for the initiation and propagation of radial hydraulic fractures in low permeability materials

Brice Tanguy Alphonse Lecampion

We compare numerical predictions of the initiation and propagation of radial fluid-driven fractures with laboratory experiments performed in different low permeability materials (PMMA, cement). In particular, we choose experiments where the time evolution ...

2017

Dynamic behavior of rock during its post failure stage in SHPB tests

Yang Zou, Yang Zhao, Xin Cai

In order to investigate the micro-process and inner mechanism of rock failure under impact loading, the laboratory tests were carried out on an improved split Hopkinson pressure bar (SHPB) system with synchronized measurement devices including a high-speed ...

Elsevier Science Bv2017

Hydroacoustic Modeling of a Cavitation Vortex Rope for a Francis Turbine

Christian Landry

Hydraulic machines subject to off-design operation involve the presence of cavitating flow regimes in the draft tube. The cavitation vortex rope at part load conditions is described as an excitation source for the hydraulic system, and interactions between ...

EPFL2015

Turbulence anisotropy in a compound meandering channel with different submergence conditions

Mário Jorge Rodrigues Pereira Da Franca

The understanding of the physical processes related to flows on compound meandering channels is a challenge given their highly 3D and complex characteristics. Three-dimensional ADV measurements were made in three cross-sections on a 1:20 physical Froude mo ...

Elsevier2015

Two-phase air-water flows: Scale effects in physical modelling

Michael Pfister

Physical modeling represents probably the oldest design tool in hydraulic engineering together with analytical approaches. In free surface flows, the similitude based upon a Froude similarity allows for a correct representation of the dominant forces, name ...

Elsevier Science Inc2014

Mitigation measures for fish habitat improvement in Alpine rivers affected by hydropower operations

Anton Schleiss, Martin Peter Bieri, Émilie Person, Armin Julius Peter

In mountainous areas, high-head-storage hydropower plants produce peak load energy. The resulting unsteady water release to rivers, called hydropeaking, alters the natural flow regime. Mitigating the adverse impacts of hydropeaking on aquatic ecosystems ha ...

John Wiley and Sons2014

Scale Effects in Modelling Two-phase Air-water Flows

Michael Pfister

Beside analytical approaches, physical modelling represents probably the oldest design tool in hydraulic engineering. For free surface flows, the similitude according to a Froude similarity allows for a correct representation of the dominant forces, namely ...

TPU2013

Hydraulic design of the diaphragm’s orifice at the entrance of the surge shaft of FMHL pumped-storage power plant

Giovanni De Cesare, Christophe Nicolet, Fadi Hachem, Rafael Xavier Meriade Duarte

The surge tank located at the upstream head of penstocks and shafts of hydropower plants is an effective measure to protect the headrace tunnels against high pressure fluctuations. It reflects the transient pressure waves that are generated by the variatio ...

TPU2013

Phase Analysis of the Stretching Cycles of the Head of Unsteady Gravity Currents Developing over Smooth and Rough Beds

Mário Jorge Rodrigues Pereira Da Franca, Helena Isabel Dos Santos Nogueira, Claudia Adduce

Gravity currents are buoyancy driven flows occurring spontaneously in nature or resulting from human intervention. Examples of gravity currents in the water are oceanic fronts, resulting from differences in temperature and salinity, and turbidity currents ...

Chengdu University Press2013

Effect of Hydrofoil Trailing Edge Geometry on the Wake Dynamics

Amirreza Zobeiri

In the present study, the effect of a hydrofoil trailing edge shape on the wake dynamic and its interaction with the mechanical structure is investigated. This would help better describe the physical reasons for vibration reduction when using oblique and D ...

EPFL2012

Forced and Self Oscillations of Hydraulic Systems Induced by Cavitation Vortex Rope of Francis Turbines

Sébastien Alligné

With economical energy market strategies based on instantaneous pricings of electricity as function of the demand or the predictions, operators harness more hydroelectric facilities to off-design operating points to cover the variations of the electricity ...

EPFL2011

The influence of shear layer thickness on the stability of confined two-dimensional wakes

François Gallaire, Luca Biancofiore

The influence of confinement onto the inviscid and incompressible linear stability of the family of wakes introduced by Monkewitz [Phys. Fluids 31, 999 (1988)] is examined. The nondimensional parameters of the model, the velocity ratio Λ, defined as ratio ...

2011

Impact Load Measurements in an Erosive Cavitating Flow

Ayat Karimi, Jean-Pierre Franc

Impact load measurements were carried out in a high-speed cavitation loop by means of a conventional pressure sensor flush-mounted in the region of closure of the cavity where maximum damage was observed. The sensor was dynamically calibrated by the ball d ...

2011

Intracranial Stents Being Modeled as a Porous Medium: Flow Simulation in Stented Cerebral Aneurysms

Nikolaos Stergiopoulos, Philippe Reymond, Luca Augsburger

Intracranial aneurysms may be treated by flow diverters, alternatively to stents and coils combination. Numerical simulation allows the assessment of the complex nature of aneurismal flow. Endovascular devices present a rather dense and fine strut network, ...

Springer US2011

The spatial variability of vehicle densities as determinant of urban network capacity

Nikolaos Geroliminis, Seyyed Amin Mazloumian

Due to the complexity of the traffic flow dynamics in urban road networks, most quantitative descriptions of city traffic so far have been based on computer simulations. This contribution pursues a macroscopic (fluid-dynamic) simulation approach, which fac ...

2010