Publications associées à Formation of the cavity on a planar interface subjected to a perturbed shock wave

Crack front waves: A 3D dynamic response to a local perturbation of tensile and shear cracks

Jean-François Molinari, Fabian Barras, Damien Spielmann, Fatima-Ezzahra Fekak

Crack front waves are long-lived perturbations propagating along the crack front. They are triggered by heterogeneities on the crack plane, as for instance tough asperities, which disturb the crack front shape. Crack front waves are thought to leave a trac ...

PERGAMON-ELSEVIER SCIENCE LTD2020

Constraint-aware neural networks for Riemann problems

Jan Sickmann Hesthaven, Deep Ray

Neural networks are increasingly used in complex (data-driven) simulations as surrogates or for accelerating the computation of classical surrogates. In many applications physical constraints, such as mass or energy conservation, must be satisfied to obtai ...

ACADEMIC PRESS INC ELSEVIER SCIENCE2020

Comparative study between Cubic and Ellipsoidal Fokker-Planck kinetic models

Mohammadhossein Gorji

Motivated by improving the performance of particle-based Monte-Carlo simulations in the transitional regime, Fokker–Planck kinetic models have been devised and studied as approximations of the Boltzmann collision operator. By generalizing the linear drift ...

2019

Collapse phenomena of deformed cavitation bubbles

Outi Supponen

Cavitation bubbles are a topic of long-standing interest owing to the powerful phenomena associated with their collapse. Their unique ability to focus energy typically causes damage in hydraulic machinery (turbines, pumps, propellers, ...) but, if managed ...

EPFL2017

Impact of rotating and fixed nozzles on vortex breakdown in compressible swirling jet flows

Leonhard Kleiser, François Gallaire

Vortex breakdown of swirling, round jet flows is investigated in the compressible, subsonic regime by means of Direct Numerical Simulation (DNS). This is achieved by solving the compressible Navier-Stokes equations on a cylindrical grid using high-order sp ...

Elsevier2016

Efficient Absorbing Layers for Weakly Compressible Flows

Jan Sickmann Hesthaven, Zhen Gao

Seeking to develop efficient and accurate absorbing layers for the low-speed weakly compressible Navier-Stokes equations, we exploit the connection to the BGK-approximation to develop an absorbing layer with qualities similar to that of the perfectly match ...

2016

Flow simulation of a Pelton bucket using finite volume particle method

François Avellan, Christian Vessaz, Ebrahim Jahanbakhsh

The objective of the present paper is to perform an accurate numerical simulation of the high-speed water jet impinging on a Pelton bucket. To reach this goal, the Finite Volume Particle Method (FVPM) is used to discretize the governing equations. FVPM is ...

International Association For Hydraulic Research2014

High Voltage Pulsed DBD Effects on the Aerodynamic Performances and on the Shock Buffet

Christoph Hollenstein, Pénélope Leyland, Peter Ott, Philip Peschke

The applications of surface dielectric barrier discharge plasma actuators, (DBD), have known a considerable interest recently in the field of flow control. In general, such actuators consist of two electrodes separated by an insulation covering the lower e ...

2013

Characterization of the Flow Generated in an Annular Test Facility

Peter Ott, Elia Colombo, Dominique Charbonnier, Cécile Deslot

Annular cascades are particularly useful to study the three dimensional phenomena encountered in turbomachines. The Non-Rotating Annular Test Facility of the Swiss Federal Institute of Technology in Lausanne (EPFL) consists in a radial-axial inlet nozzle a ...

2011

Investigation on the Three-Dimensional Flow Mechanisms in Annular Axial Compressor Cascades for Aero Engines with Flow Control by Aspiration on the Hub and on the Blades

Elia Colombo

The axial compressor is an essential component of aero-engines and gas turbines. This work investigates how flow control by aspiration applied to the hub and to the blades of axial compressor wheels can improve the static pressure rise by preventing detrim ...

EPFL2011

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

Caractérisation de la génération et la propagation d'ondes de pressions dans des tissus biologiques pour la conception d'appareils médicaux

Mathieu Benoit

Therapies using so called extracorporeal shock waves (Extracorporeal Shock Wave Therapy ESWT) have become current medical practice in orthopedy and traumatology. In order to understand and to optimize the effect of shock waves in clinical applications, med ...

EPFL2009

Interaction between a surface dielectric barrier discharge and transonic airflows

Samantha Pavon

The use of plasmas in aerodynamics has become a recent topic of interest. The potentialities of different types of plasmas are being investigated for low velocity and high velocity flow control, as well as for plasma-assisted combustion. Dielectric barrier ...

EPFL2008

Effects of high-speed airflows on a surface dielectric barrier discharge

Christoph Hollenstein, Pénélope Leyland, Peter Ott, Samantha Pavon

A detailed study of the interaction between high-speed gas flows and surface dielectric barrier discharges (DBD) is presented. In the present paper, it is demonstrated that a DBD can be sustained in transonic airflows, up to isentropic Mach numbers of 1.1. ...

2007

Influence of macro-roughness of walls on steady and unsteady flow in a channel

Tobias Meile

High-head storage hydropower plants mainly operate their turbines during periods of high energy demand. The sudden starting and stopping of turbines (hydropeaking) lead to highly unsteady flow in channels and rivers. Besides hydropeaking, other anthropogen ...

EPFL2007

Highly loaded compressor with boundary layer suction

Klaus Hubrich

An experimental and numerical investigation of boundary layer suction (BLS) on a transonic compressor blade has been conducted. The objective of the present work is to identify the possible benefit of boundary layer suction via a slot in the region of the ...

EPFL2005

Characterization of supersonic low pressure plasma jets

Malko Gindrat

Low Pressure Plasma Spraying (LPPS) processes use a DC plasma jet expanding at low pressure for fast deposition of dense coatings in a controlled atmosphere. The LPPS technology is widely used industrially in particular in the aeronautics and medical indus ...

EPFL2004