Publications associées à How oblique trailing edge of a hydrofoil reduces the vortex-induced vibration

The dynamics and timescales of static stall

Karen Ann J Mulleners, Sébastien Le Fouest, Julien Dominique Claude Deparday

Airfoil stall plays a central role in the design of safe and efficient lifting surfaces. We typically distinguish between static and dynamic stall based on the unsteady rate of change of an airfoil’s angle of attack. Despite the somewhat misleading denotat ...

2021

Th1509U European 170 Ghz 1 Mw Cw Industrial Gyrotron Upgrade

Stefano Alberti, Jean-Philippe Hogge, Francisco Sanchez, Ioannis Pagonakis, Konstantinos Avramidis

This paper describes the status on the upgrade of the first European gyrotron prototype for ITER, manufactured by Thales. The upgraded prototype, TH1509U, is now being tested to verify the performance improvements and to assess the compliance with ITER ECR ...

IEEE2021

A new Euler-Lagrangian cavitation model for tip-vortex cavitation with the effect of non-condensable gas

Mohamed Farhat, Huaiyu Cheng

Numerical simulation of tip vortex cavitation (TVC) remains a challenging task in a variety of applica-tions, such as axial turbines and pumps as well as marine propellers. Although it is well known that TVC is highly sensitive to gas content, be it dissol ...

PERGAMON-ELSEVIER SCIENCE LTD2021

Group testing for connected communities

Pavlos Nikolopoulos, Christina Fragouli, Suhas Diggavi, Sundara Rajan Srinivasavaradhan

In this paper, we propose algorithms that leverage a known community structure to make group testing more efficient. We consider a population organized in disjoint communities: each individual participates in a community, and its infection probability depe ...

MICROTOME PUBLISHING2021

Exploring policy change through agent-based simulation

Raphaël Klein

Policymaking is a complex process that has been studied using policy process theories almost exclusively. These theories have been built using a large number of qualitative cases. Such methods are useful for theory building but remain limited for theory ex ...

EPFL2021

On the numerical simulation of a confined cavitating tip leakage vortex under geometrical and operational uncertainties

Mohamed Farhat

The effects of operational and geometrical uncertainties on Tip Leakage Vortex (TLV) characteristics are investigated in the current research. Geometrical uncertainties are comprised of manufacturing tolerances or gradual geometry degradation over the time ...

PERGAMON-ELSEVIER SCIENCE LTD2021

Dynamic stall on an airfoil undergoing VAWT blade angle of attack variations

Karen Ann J Mulleners, Sébastien Le Fouest, Sabrina Henne

Vertical axis wind turbines have several attractive features in the context of energy production in urban areas, but the inherent aerodynamic complexity of the flow around them has challenged their development on a larger scale. They generally operate at l ...

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

A point vortex transportation model for yawed wind turbine wakes

Fernando Porté Agel, Haohua Zong

In this study, stereo particle imaging velocimetry measurements are performed at multiple streamwise locations behind a yawed wind turbine to reveal the formation mechanisms of the counter-rotating vortex pair (CVP), and a point vortex transportation (PVT) ...

Cambridge University Press2020

Stall Delay and Leading-Edge Suction for a Pitching Airfoil with Trailing-Edge Flap

Karen Ann J Mulleners, Julien Dominique Claude Deparday, Guosheng He

The flow around a pitching NACA0015 airfoil with an oscillating trailing-edge flap is experimentally investigated to characterize the influence of the flap kinematics on the development of dynamic stall. We specifically focus on the timing of the stall dev ...

2020