Publications associées à Experiments of flow separation at the inner bank of open-channel bends

Indentation and stability of woven domes

Célestin Vallat, Pedro Miguel Nunes Pereira de Almeida Reis, Tomohiko Sano, Tian Chen, Samuel Jean Bernard Poincloux

Discrete domes are doubly curved structures comprising a network of beam-like elements. We study the mechanics of discrete domes made of ribbons woven in a pentagonal triaxial pattern. Experiments and finite element simulations are performed to characteriz ...

ELSEVIER2023

Self-sustained dynamics and forced resonant oscillations in flows: cross-junction jets and sloshing liquids

Alessandro Bongarzone

In engineering, oscillatory instabilities and resonances are often considered undesirable flow features and measures are taken to avoid them. This may include avoiding certain parametric regions or implementing control and mitigation strategies. However, t ...

EPFL2023

Data-driven modeling of beam loss in the LHC

Tatiana Pieloni, Michael Schenk, Loïc Thomas Davies Coyle, Ekaterina Krymova

In the Large Hadron Collider, the beam losses are continuously measured for machine protection. By design, most of the particle losses occur in the collimation system, where the particles with high oscilla-tion amplitudes or large momentum error are scrape ...

FRONTIERS MEDIA SA2023

A wind tunnel study on cyclic yaw control: Power performance and wake characteristics

Fernando Porté Agel, Arslan Salim Dar, Guiyue Duan

In this study, wind-tunnel experiments are used to investigate cyclic yaw control as a wake mitigation strategy aiming to improve wind farm power production. The control strategy is applied to a single wind turbine and a wind farm comprising of a column of ...

Elsevier2023

Robust optimization of control parameters for WEC arrays using stochastic methods

Edie Miglio, Tommaso Vanzan

This work presents a new computational optimization framework for the robust control of parks of Wave Energy Converters (WEC) in irregular waves. The power of WEC parks is maximized with respect to the individual control damping and stiffness coefficients ...

Journal of Computational Physics2023

Scaling behavior of bedload transport: what if Bagnold was right?

Christophe Ancey

There is a paradox in the relationship between bedload transport rates and flow variables: laboratory and field studies have reported on how bedload transport rates depend on flow variables through a power law, but none of the empirical laws fitted to the ...

2023

Invariant states in inclined layer convection. Part 2. Bifurcations and connections between branches of invariant states

Tobias Schneider, Florian Reetz

Convection in a layer inclined against gravity is a thermally driven non-equilibrium system, in which both buoyancy and shear forces drive spatio-temporally complex flows. As a function of the strength of thermal driving and the angle of inclination, a mul ...

Cambridge University Press2020

Nature of Crack Path Instabilities in Thin Sheets Cut by Blunt Objects

Iryna Sivak

Cutting a brittle thin sheet with a blunt object leaves an oscillating crack that seemingly violates the principle of local symmetry for fracture. We experimentally find that at a critical value of a well chosen control parameter the straight propagation i ...

AMER PHYSICAL SOC2020

A hybrid control strategy for force and precise end effector positioning of a twisted string actuator

Jamie Paik, Andres San Millan Rodriguez

We propose a new control approach for the twisted string actuation (TSA) system; a hybrid control scheme consisting of two nested loops, considering the motor angle and the axial force at the clamping point of the actuator as the system outputs. We show th ...

2021

A solution method for predictive simulations in a stochastic environment

Anne Daniëlle Koelewijn

Predictive gait simulations currently do not account for environmental or internal noise. We describe a method to solve predictive simulations of human movements in a stochastic environment using a collocation method. The optimization is performed over mul ...

2020

Turbulent patterns in wall-bounded shear flows: invariant solutions and their bifurcations

Florian Reetz

When laminar shear flows in large wall-bounded domains transition to turbulence, the flow exhibits spatio-temporally chaotic dynamics. Despite its chaotic dynamics, the flow may self-organize into characteristic spatially periodic patterns of unknown origi ...

EPFL2019

Second-order sensitivity in the cylinder wake: Optimal spanwise-periodic wall actuation and wall deformation

François Gallaire, Edouard Boujo, Andrea Fani

Two-dimensional (2D) flows can be controlled efficiently using spanwise "waviness," i.e., a control (e.g., wall blowing and suction or wall deformation) that is periodic in the spanwise direction. This study tackles the global linear stability of 2D flows ...

AMER PHYSICAL SOC2019

From standing balance to walking: A single control structure for a continuum of gaits

Auke Ijspeert, Seyed Hamed Razavi, Salman Faraji

This article presents a control algorithm framework with which a bipedal robot can perform a variety of gaits by only modifying a small set of control parameters. The controller drives a number of variables, called non-emergent variables, to their desired ...

2019

Design of Magnetic Bearing Control System Based on Active Disturbance Rejection Theory

Yuanping Xu

At present, most of the magnetic bearing system adopts the classical proportional-integral-derivative (PID) control strategy. However, the external disturbances, system parameter perturbations, and many other uncertain disturbances result in PID controller ...

2019

Response of noise-amplifier flows: From linear control to nonlinear jet breakup

Isha Shukla

Among hydrodynamically unstable flows, the amplifier-flows are characterized by their large amplification potential in presence of external noise. Since amplifiers do not have an intrinsic dynamics, a chosen forcing can be applied to eventually control the ...

EPFL2019

Linear-parameter-varying model predictive control for multi-region traffic systems

Nikolaos Geroliminis, Mohammadreza Saeedmanesh, Anastasios Kouvelas

An alternative approach for real-time network-wide traffic control in cities that has recently gained a lot of interest is perimeter flow control. The basic concept of such an approach is to partition heterogeneous cities into a small number of homogeneous ...

2019

Voltage Control in Active Distribution Networks Under Uncertainty in the System Model: A Robust Optimization Approach

Mario Paolone, Konstantina Christakou, Ali Abur

Within the context of ancillary services for Active Distribution Networks (ADNs), application of intelligent control techniques is required in order to achieve specific operation objectives. Despite their differences, most control mechanisms proposed in th ...

2018

Biomimetic adaptive control of a deployable tensegrity structure

Ann Christine Sychterz

Biomimetic behavior includes aspects such as learning from previous experience, self-diagnosis, and adaptation. This thesis describes control methodologies that are essential to development towards biomimetic behavior of a complex deployable structure. Sim ...

EPFL2018

Strategies for faster impregnation in melt thermoplastic resin transfer molding process

Damiano Salvatori

Continuous fiber thermoplastic composites are potential substitutes of steel in structural automotive components, since they combine fiber strength and rigidity with ductility, potential recyclability and low density of the thermoplastic (TP) matrix. Resin ...

EPFL2018

Optimisation of Current and Pulse Duration in Electric Discharge Drilling of D2 Steel Using Graphite Electrode

Electric discharge machining (EDM) is one of the viable techniques for machining of D2 steel, in which the material removal occurs by spark erosion. The poor selection of EDM parameters affect the machining quality and productivity. Considering this, the p ...

2018