Publications associées à Acoustic tomography for scalar and vector fields: theory and application to temperature and wind estimation

Publications associées (27)

Turbulence and Heat exchange in the Near-Surface Boundary Layer over Patchy Snow

The atmospheric layer adjacent to the earth's surface is of crucial importance for weather models due to the exchange of energy between the surface and the atmosphere. This exchange is dependent on the various surface properties and influences the state of ...

EPFL2024

Improvements to the dynamic wake meandering model by incorporating the turbulent Schmidt number

Fernando Porté Agel, Peter Andreas Brugger, Corey Dean Markfort

Predictions of the dynamic wake meandering model (DWMM) were compared to flow measurements of a scanning Doppler lidar mounted on the nacelle of a utility-scale wind turbine. We observed that the wake meandering strength of the DWMM agrees better with the ...

2024

3D printed large amplitude torsional microactuators powered by ultrasound

Mahmut Selman Sakar, Amit Yedidia Dolev, Mehdi Ali Gadiri, Junsun Hwang

Here, we introduce a design, fabrication, and control methodology for large amplitude torsional microactuators powered by ultrasound. The microactuators are 3D printed from two polymers with drastically different elastic moduli as a monolithic compliant me ...

2024

Comparison of selected surface level ERA5 variables against in‐situ observations in the continental Arctic

Julia Schmale, Jakob Boyd Pernov

In this study, data from 17 ground-based, continental Arctic observatories areused to evaluate the performance of the European Centre for Medium-RangeWeather Forecasts Reanalysis version 5 (ERA5) reanalysis model. Three aspectsare evaluated: (i) the overal ...

2024

Towards an improved understanding of wind turbine wakes in complex terrain

Arslan Salim Dar

In this thesis, we explored the effect of certain terrain-induced flow phenomena on the development of wind turbines sited in complex terrain. A combined experimental and analytical approach is used to study wind turbine wakes in different types of complex ...

EPFL2024

Scattering from Time-Modulated Transmission-Line Loads: Theory and Experiments in Acoustics

Romain Christophe Rémy Fleury, Matthieu Francis Malléjac

Scattering wave systems that are periodically modulated in time offer many new degrees of freedom to control waves in both the spatial and frequency domains. Such systems, albeit linear, do not conserve frequency and require the adaptation of the usual the ...

American Physical Society (APS)2023

Wind Turbine Wakes in Active Yaw Control: Numerical and Theoretical Studies

Mou Lin

In this thesis, we explore the best practice of simulating the wakes of the turbines under active yaw control (AYC) using large-eddy simulation (LES). In the first study, we validate the blade-element actuator disk model (ADM-BE) for a yawed wind turbine. ...

EPFL2023

Advancing efficiency and reliability in thermal analysis of laser powder-bed fusion

Christian Leinenbach

In laser based powder-bed fusion of metals (PBF-LB/M), parts are fabricated by melting layers of powder using a high-intensity laser beam. During this process, the material is exposed to rapid cooling rates and intense thermal gradients, which are the unde ...

2023

MoMuCAMS: A new modular platform for boundary layer aerosol and trace gas vertical measurements in extreme environments

Julia Schmale, Andrea Baccarini, Roman Pohorsky

The Modular Multiplatform Compatible Air Measurement System (MoMuCAMS) is a newly developed in situ aerosol and trace gas measurement payload for lower atmospheric vertical profiling in extreme environments. MoMuCAMS is a multiplatform compatible system, p ...

2023

Natural slicks on Lake Geneva: From small-scale effects to large-scale formation and distribution

Mehrshad Foroughan

Low wind speeds (< 4 m/s) are ubiquitous in many water bodies, yet the physical processes occurring at the air-water interface in this range are poorly understood. A notable example is smooth patches on the water surface, known as natural slicks, formed wh ...

EPFL2023

Scaling Description of Dynamical Heterogeneity and Avalanches of Relaxation in Glass-Forming Liquids

Matthieu Wyart

We provide a theoretical description of dynamical heterogeneities in glass-forming liquids, based on the premise that relaxation occurs via local rearrangements coupled by elasticity. In our framework, the growth of the dynamical correlation length e and o ...

American Physical Society2023

Power Production and Blade Fatigue of a Wind Turbine Array Subjected to Active Yaw Control

Fernando Porté Agel, Mou Lin

This study investigated the power production and blade fatigue of a three-turbine array subjected to active yaw control (AYC) in full-wake and partial-wake configurations. A framework of a two-way coupled large eddy simulation (LES) and an aeroelastic blad ...

MDPI2023

Setting priorities in CNF particle size measurement: What is needed vs. what is feasible

Tiffany Abitbol

Measuring the size of cellulose nanomaterials can be challenging, especially in the case of branched and entangled cellulose nanofibrils (CNFs). The International Organization for Standardization, Technical Committee 6, Task Group 1-Cellulosic Nanomaterial ...

TECH ASSOC PULP PAPER IND INC2023

Vibrational NDT with Under-sampled Data through Physics-informed Neural Networks

Olga Fink

The vibrational response of solid materials and structural components is substantially governed by their mechanical and geometrical properties. Low-frequency vibrations and modal frequencies are sensitive to global geometrical deviations, while high-freque ...

2023

Wind-Topo: Downscaling near-surface wind fields to high-resolution topography in highly complex terrain with deep learning

Michael Lehning, Jérôme François Sylvain Dujardin

Predicting wind flow in highly complex terrain like the Alps is a challenge for all models. When physical processes need to be resolved in a spatially explicit manner, grids with high horizontal resolution of a few hundred meters are often required and dra ...

WILEY2022

Improved spiking neural network for intershaft bearing fault diagnosis

Jun Wang

The intershaft bearing is located between the high and low-pressure rotors of the aero-engine, where the working environment is harsh, the load variation range is large, and the lubrication and heat dissipation are poor. The fault of the intershaft bearing ...

ELSEVIER SCI LTD2022

3D Printed Acoustically Programmable Soft Microactuators

Mahmut Selman Sakar, Murat Kaynak, Amit Yedidia Dolev

The concept of creating all-mechanical soft microrobotic systems has great potential to address outstanding challenges in biomedical applications, and introduce more sustainable and multifunctional products. To this end, magnetic fields and light have been ...

2023

Mathematical Foundations of Adaptive Isogeometric Analysis

Annalisa Buffa, Rafael Vazquez Hernandez

This paper reviews the state of the art and discusses recent developments in the field of adaptive isogeometric analysis, with special focus on the mathematical theory. This includes an overview of available spline technologies for the local resolution of ...

SPRINGER2022

Ultra low quantum decoherence nano-optomechanical systems

Mohammadjafar Bereyhi

Thermal motion of a room-temperature mechanical resonator typically dominates the quantum backaction of its position measurement. This is a longstanding barrier for exploring cavity optomechanics at room temperature. In order to enter the quantum regime of ...

EPFL2022

Assessment of the Bundle SNSPD Plus FPGA-Based TDC for High-Performance Time Measurements

Christophe Marcel Georges Galland, Santiago Tarrago Velez

Counting single photons and measuring their arrival time is of crucial importance for imaging and quantum applications that use single photons to outperform classical techniques. The investigation of the coincidence, i.e. correlation, between photons can b ...

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC2022