Publications related to Continuity equation

Mean-field transport equations and energy theorem for plasma edge turbulent transport

This paper establishes a mean-field equation set and an energy theorem to provide a theoretical basis in view of the development of self-consistent, physics-based turbulent transport models for mean-field transport codes. A rigorous averaging procedure ide ...

Cambridge University Press2024

Anomalous dissipation and other non-smooth phenomena in fluids

Massimo Sorella

The thesis is dedicated to the study of two main partial differential equations (PDEs) in fluid dynamics: the Navier-Stokes equations, which describe the motion of incompressible fluids, and the transport equation with divergence-free velocity fields, whic ...

EPFL2024

Quantitative convergence rates for scaling limit of SPDEs with transport noise

Lucio Galeati

We consider on the torus the scaling limit of stochastic 2D (inviscid) fluid dynamics equations with transport noise to deterministic viscous equations. Quantitative estimates on the convergence rates are provided by combining analytic and probabilistic ar ...

Academic Press Inc Elsevier Science2024

LDP and CLT for SPDEs with transport noise

Lucio Galeati

In this work we consider solutions to stochastic partial differential equations with transport noise, which are known to converge, in a suitable scaling limit, to solution of the corresponding deterministic PDE with an additional viscosity term. Large devi ...

SPRINGER2023

ALMOST EVERYWHERE NONUNIQUENESS OF INTEGRAL CURVES FOR DIVERGENCE-FREE SOBOLEV VECTOR FIELDS

Massimo Sorella

We construct divergence-free Sobolev vector fields in C([0,1];W-1,W-r(T-d;Rd)) with r < d and d\geq 2 which simultaneously admit any finite number of distinct positive solutions to the continuity equation. These vector fields are then shown to have at leas ...

Siam Publications2023

Convection of snow: when and why does it happen?

Michael Lehning, Mahdi Jafari

Convection of water vapor in snowpacks is supposed to have a major impact on snow density and microstructure profiles with strong implications for the thermal regime and snow stability. However, the process has never been directly measured and only recentl ...

FRONTIERS MEDIA SA2023

Lp-regularity theory for the stochastic reaction-diffusion equation with super-linear multiplicative noise and strong dissipativity

Jaeyun Yi

We study the existence, uniqueness, and regularity of the solution to the stochastic reaction-diffusion equation (SRDE) with colored noise F-center dot:partial derivative(t)u = aijuxixj +biuxi + cu - bu1+beta +xi u1+gamma F-center dot, (t, x) is ...

Academic Press Inc Elsevier Science2023

Wigner Formulation of Thermal Transport in Solids

Nicola Marzari, Michele Simoncelli

Two different heat-transport mechanisms are discussed in solids. In crystals, heat carriers propagate and scatter particlelike as described by Peierls's formulation of the Boltzmann transport equation for phonon wave packets. In glasses, instead, carriers ...

American Physical Society2022

Construction of Fe3O4 bridged Pt/g-C3N4 heterostructure with enhanced solar to fuel conversion

Michael Graetzel, Shaik Mohammed Zakeeruddin

In this study, we report the effects of co-catalysts of Pt nanoparticles and Fe3O4 clusters on photocatalytic behaviors of g-C3N4 (CN) and the use of the resulting photocatalyst for CO2 photoreduction to solar fuels in a flow reactor operated at room-tempe ...

ELSEVIER2022

Analytic modelling of passive microfluidic mixers

Jean-Michel Sallese, Christophe Lallement

This paper deals with a new analytical model for microfluidic passive mixers. Two common approaches already exist for such a purpose. On the one hand, the resolution of the advection-diffusion-reaction equation (ADRE) is the first one and the closest to ph ...

AMER INST MATHEMATICAL SCIENCES-AIMS2022

Positive Solutions of Transport Equations and Classical Nonuniqueness of Characteristic curves

Maria Colombo, Camillo De Lellis

The seminal work of DiPerna and Lions (Invent Math 98(3):511-547, 1989) guarantees the existence and uniqueness of regular Lagrangian flows for Sobolev vector fields. The latter is a suitable selection of trajectories of the related ODE satisfying addition ...

2021

Development of a novel two-phase flow solver for nuclear reactor analysis: algorithms, verification and implementation in OpenFOAM

Andreas Pautz, Carlo Fiorina, Stefan Radman

A porous medium-based representation of nuclear reactors and complex engineering systems more in general can significantly reduce simulation and modelling costs, while preserving a reasonable degree of accuracy via regime map-based correlations for modelli ...

2021

Investigation of the Time Resolution Set Up Used to Compute the Full Load Vortex Rope in a Francis Turbine

François Avellan, Andres Müller, Arthur Tristan Favrel, Cécile Münch-Alligné

The flow in a Francis turbine at full load is characterised by the development of an axial vortex rope in the draft tube. The vortex rope often promotes cavitation if the turbine is operated at a sufficiently low Thoma number. Furthermore, the vortex rope ...

2021

Evidence of a J/psi Lambda structure and observation of excited Xi(-) states in the Xi(-)(b) -> J/psi Lambda K- decay

Lesya Shchutska, Olivier Schneider, Aurelio Bay, Yiming Li, Guido Haefeli, Frédéric Blanc, Christoph Frei, Tatsuya Nakada, Michel De Cian, Elena Graverini, Veronica Sølund Kirsebom, François Fleuret, Ettore Zaffaroni, Matthieu Philippe Luther Marinangeli, Renato Quagliani, Federico Betti, Minh Tâm Tran, Donal Patrick Hill, Aravindhan Venkateswaran, Pietro Marino, Vitalii Lisovskyi, Federico Leo Redi, Katharina Müller, Violaine Bellée, Maria Vieites Diaz, Elisabeth Maria Niel, Pavol Stefko, Tara Nanut, Jian Wang, Maria Elena Stramaglia, Mingkui Wang, Vladimir Macko, Guillaume Max Pietrzyk, Zhirui Xu, Chao Wang, Sebastian Schulte, Lino Ferreira Lopes, Yi Zhang, Surapat Ek-In, Lei Zhang, , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , ,

An adaptive algorithm for the transport equation with time dependent velocity

Marco Picasso, Samuel Dubuis

An a posteriori error estimate is derived for the approximation of the transport equation with a time dependent transport velocity. Continuous, piecewise linear, anisotropic finite elements are used for space discretization, the Crank-Nicolson scheme schem ...

2020

Continuously-fed density currents over impermeable and porous substrates

Sara Venuleo

Gravity currents are buoyancy-driven flows having a significant impact on the environment and human life. They can be observed in a vast range of natural and anthropogenic scenarios, such as seawater and freshwater, the atmosphere, or industrial processes. ...

EPFL2020

Direct numerical simulation of phase change in the presence of non-condensable gases

Lubomír Bures, Yohei Sato

This paper describes a new numerical method for the simulation of phase change phenomena between a liquid and a vapour in the presence of non-condensable gases. The method is based on an interface-tracking approach in the framework of single-fluid modellin ...

2020

Numerical Simulation and Validation of Aerosol Particle Removal by Water Spray Droplets With OpenFOAM During the Fukushima Daiichi Fuel Debris Retrieval

Hui Liang

In the decommissioning of damaged Fukushima Daiichi reactors, the melted and re-solidified fuel debris in the bottom of the reactor pressure vessel and primary containment vessel need to be cut into small pieces before removing them from reactor buildings. ...

2020

Structural, electronic, elastic, power, and transport properties of beta-Ga2O3 from first principles

Samuel Poncé, Feliciano Giustino

We investigate the structural, electronic, vibrational, power, and transport properties of the beta allotrope of Ga2O3 from first principles. We find phonon frequencies and elastic constants that reproduce the correct band ordering, in agreement with exper ...

2020

Dynamics of optical forces and torques in plasmonic systems: a surface integral equation

Olivier Martin, Karim Achouri, Andrei Kiselev

A novel approach is introduced to determine the time evolution of optical forces and torques on arbitrary shape nanostructures by combining Maxwell's stress tensor with the surface integral equation method (SIE). Conventional time averaging of Maxwell’s st ...

SPIEDigitalLibrary2020