Modeling Group

@article{yakoubi_1803,

title = {Characteristics/finite element analysis for two incompressible fluid flows with surface tension using level set method},

author = {Driss Yakoubi and Christine Bernardi and Sarra Maarouf},

url = {https://www.sciencedirect.com/science/article/pii/S0045782522001530},

year  = {2022},

date = {2022-03-01},

journal = {Computer Methods In Applied Mechanics And Engineering},

volume = {394},

number = {XXXX},

pages = {Paper No. 114843},

abstract = {In this paper, we present and analyze a finite element level set method based on the method of characteristics for two phase

flow. Surface tension effects are taken into account by the CSF approach. We first write the variational formulation of the problem and investigate its well-posedness. Next, for the discretization, a first order method of characteristics approach for the

evolution of the level set function and for the material derivative of the velocity is used. The velocity and pressure unknowns

are discretized by P2? P1 Taylor-Hood finite elements. Then, in each time step, the interface transport is decoupled from the

Navier-Stokes equations. Well-posedness results for subproblems in this decoupled discrete problem are derived. Furthermore,

under high regularity assumptions, we state error estimates for our scheme. Ultimately, three computational examples illustrate

the performance of the proposed method.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{yakoubi_1802,

title = {A new energy stable fractional time stepping scheme for the Navier-Stokes/Allen-Cahn diffuse interface model},

author = {Driss Yakoubi and Jean Deteix and Gerard Lionel Ndetchoua Kouamoa},

url = {https://www.sciencedirect.com/science/article/pii/S0045782522001104},

year  = {2022},

date = {2022-02-01},

journal = {Computer Methods In Applied Mechanics And Engineering},

volume = {393},

number = {XXXX},

pages = {Paper No. 114759, 25},

abstract = {In this work, we present an original time-discrete formulation of the coupled equations relating the velocity and pressure

of an unsteady flow of two immiscible fluids and the Allen-Cahn equation describing the interface between both of them. We

first prove this time-discrete formulation (based on the concept of coupled projection scheme (Deteix et al., 2014)) to be well

posed and energy stable. We then propose a new family of iterative schemes for the actual approximation of solutions. We

complete this work with numerical tests illustrating the order of accuracy and applying the new scheme on the well known

rising bubble benchmark.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{yakoubi_1795,

title = {A projection scheme for phase change problems with convection},

author = {Driss Yakoubi},

url = {https://www-sciencedirect-com.acces.bibl.ulaval.ca/science/article/pii/S0898122122000013?via%3Dihub},

year  = {2022},

date = {2022-01-01},

journal = {Computers & Mathematics With Applications},

volume = {108},

number = {1},

pages = {109-122},

abstract = {Numerical modeling of phase change problems with convection is known to be computationally expensive. The main challenge comes from the coupling between Navier-Stokes and heat energy equations. In this paper, we develop a new scheme for phase change problems based on a projection method. The proposed method reduces the size of the system by splitting the temperature, the velocity, and the pressure fields while preserving the accuracy of the simulations. A single-domain approach using a variant of the enthalpy-porosity formulation is employed. Incompressible Navier-Stokes problem with Boussinesq approximation for thermal effects in solid and liquid regions is considered. We regularize the discontinuous variables such as latent heat and material properties by a continuous and differentiable hyperbolic tangent function. The robustness and effectiveness of the proposed scheme are illustrated by comparing the numerical results with numerical and experimental benchmark},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{boudin_1819,

title = {EXPONENTIAL CONVERGENCE TOWARDS CONSENSUS FOR NON-SYMMETRIC LINEAR FIRST-ORDER SYSTEMS IN FINITE AND INFINITE DIMENSIONS},

author = {Laurent Boudin and Francesco Salvarani and Emmanuel Trélat},

url = {https://epubs.siam.org/doi/abs/10.1137/21M1416102},

year  = {2022},

date = {2022-01-01},

journal = {Siam Journal On Mathematical Analysis},

volume = {54},

number = {3},

pages = {2727-2752},

abstract = {We consider finite and infinite-dimensional first-order consensus systems with time- constant interaction coefficients. For symmetric coefficients, convergence to consensus is classically established by proving, for instance, that the usual variance is an exponentially decreasing Lyapunov function. We investigate here the convergence to consensus in the non-symmetric case: we identify a positive weight which allows us to define a weighted mean corresponding to the consensus and obtain exponential convergence towards consensus. Moreover, we compute the sharp exponential decay rate.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{chami_1564,

title = {Thermodynamic characterization of mixed gas hydrates in the presence of cyclopentane as guest molecule for an application in secondary refrigeration},

author = {Nada Chami and Sabrina Bendjenni and Pascal Clain and Véronique Osswald and Anthony Delahaye and Laurence Fournaison and Didier Dalmazzone},

url = {https://www.sciencedirect.com/science/article/pii/S0009250921003559},

year  = {2021},

date = {2021-11-01},

journal = {Chemical Engineering Journal},

volume = {244},

number = {-},

pages = {116790},

abstract = {Gas hydrates have drawn the attention of many scientists because of their potential role in energy applications. By using some thermodynamic promoters, it is possible to form hydrates at reduced pressure and near ambient temperature, which are suitable formation conditions for most industries. In this study, a high pressure micro differential scanning calorimeter was used to measure the dissociation conditions of mixed cyclopentane (c-C5H10) + CO2 hydrates in the system composed of liquid water + liquid hydrocarbon + hydrate + vapour, in a pressure range of 0 to 4.3 MPa in a temperature range of 280 to 292 K. The analysis of the heat flow curve allowed the direct determination of the dissociation enthalpy of c-C5H10 + CO2 hydrates (e.g., ?H=462.5±1.5 kJ. kg-1 water at equilibrium pressure 0.25 MPa) and the average mass heat capacity of c-C5H10 + CO2 hydrates in a temperature range o 277.9-281.2 K (CpH = 1479.09 ± 137.43 J. K-1. kg-1 hydrate at 0.25 MPa).},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{ben_abdallah_1721,

title = {Modeling of viscoelastic behavior of a shape memory polymer blend},

author = {Abir Ben Abdallah and Achraf Kallel and Abbas Tcharkhtchi and Tarek Hassine and Fehmi Gamaoun},

url = {https://onlinelibrary.wiley.com/doi/10.1002/app.51859},

year  = {2021},

date = {2021-11-01},

journal = {Journal Of Applied Polymer Science},

volume = {2021},

number = {2021},

pages = {1-8},

abstract = {Shape memory effect (SME) of polymers is a property that concerns both,

macroscopic and microscopic changes. The variation of internal polymer

properties such, as molecular weight (Mw), rigidity, and viscoelasticity could

alter its SME. In this study, a bi-parabolic model with six parameters is used to

describe the viscoelastic behavior of a shape memory polymer (SMP) blend

(40% poly(caprolactone), PCL/60% Styrene-Butadiene-Styrene) with different

PCL Mw. These parameters are determined using the Cole-Cole method.

Modeling curves (E00 = f (E0)) will be then compared to experimental data from

dynamical mechanical analysis (DMA) tests. It is shown that the bi-parabolic

model predicts well the behavior of the SMP mixture for different Mw of PCL.

Afterwards, the evolution of the model parameters with the Mw of PCL is

investigated. It is revealed that, when Mw of PCL drops, the relaxation modulus

E0 increases. This result proves that the rigidity of the SMP blend rises with

Mw declines.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{guerard_1732,

title = {Isolated Areas Consumption Short-Term Forecasting Method},

author = {Guillaume Guérard and Hugo Pousseur and Ihab Taleb},

url = {https://www.mdpi.com/1996-1073/14/23/7914},

year  = {2021},

date = {2021-11-01},

journal = {Energies},

volume = {14},

number = {23},

pages = {7914},

abstract = {Forecasting consumption in isolated areas represents a challenging problem typically resolved using deep learning or huge mathematical models with various dimensions. Those models require expertise in metering and algorithms and the equipment needs to be frequently maintained. In the context of the MAESHA H2020 project, most of the consumers and producers are isolated. Forecasting becomes more difficult due to the lack of external data and the significant impact of human behaviors on those small systems. The proposed approach is based on data sequencing, sequential mining, and pattern mining to infer the results into a Hidden Markov Model. It only needs the consumption and production curve as a time series and adapts itself to provide the forecast. Our method gives a better forecast than other prediction machines and deep-learning methods used in literature review.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{guerard_1604,

title = {USoM platform. Proposal for an international and transdisciplinary interactive tool for centralization and anthropological exchange around human remains},

author = {Guillaume Guérard and Sofiane Ben Amor and Philippe Charlier and Anais Augias},

url = {https://www.sciencedirect.com/science/article/pii/S2352552521000542},

year  = {2021},

date = {2021-09-01},

journal = {ETHICS, MEDICINE AND PUBLIC HEALTH},

volume = {18},

number = {September},

pages = {1-6},

abstract = {Background



In a previous article related to ethical reflection around the study of human remains and their biological products in archaeological, ethnographic and museum contexts, a general scientific isolation - going against the common interest and leading to certain forms of misconduct - had been raised. It appeared a real need to act in the direction of transparency and a transdisciplinary union.

Methodology



This conclusion led to further reflection on the strengths and technical creation of a tool dedicated to the exchange between sciences relating to the study of man.

Results/Discussion



We propose the creation of a platform dedicated to all international scientific actors whose issues are related to research on humans. This involves proposing the development of a participatory/collaborative virtual platform on which scientific organizations would exchange their study materials, their samples, their tools, their knowledge, their reflections and hypotheses and then the resulting data in order to no longer work in isolation.

Conclusion/Perspectives



This multidisciplinary vision to the study of Man, without spatial or chronological boundaries, will be a contribution to each of the disciplines involved and the benefits of this platform are multiple. However, this coalition approach exposes academic, technical and legal difficulties and represents a real challenge because it requires profound changes.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{jaffal-moutarda_1356,

title = {Global existence of the 3D rotating second grade fluid system},

author = {Basma Jaffal-Moutarda},

url = {https://content.iospress.com/articles/asymptotic-analysis/asy201644},

year  = {2021},

date = {2021-08-01},

journal = {Asymptotic Analysis},

volume = {124},

number = {3-4},

pages = {259-290},

abstract = {We consider the equations of a rotating incompressible non-Newtonian fluid flow of grade two in a three dimensional torus. We prove two different results of global existence of strong solutions. In the first case, we consider that the elasticity coefficient ? is arbitrary and we suppose that the third components of the vertical average of the initial data and of the forcing term are small compared to the horizontal components. In the second case, we consider a forcing term and initial data of arbitrary size but we restrict the size of ?. In both cases, we show that the limit system is composed of a linear system and a second grade fluid system with two variables and three components.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{kallel_1585,

title = {Driving force for shape memory effect of polymers},

author = {Achraf Kallel and Abir Ben Abdallah and Fehmi Gamaoun and Abbas Tcharkhtchi and Hachmi BenDaly and Joseph Fitoussi},

url = {https://link.springer.com/article/10.1007/s10965-021-02637-4},

year  = {2021},

date = {2021-07-01},

journal = {Journal Of Polymer Research},

volume = {28},

number = {10},

pages = {308},

abstract = {In this study, we aim to evaluate the shape memory effect of a Poly (Caprolactone) (PCL) (40%) and a Styrene-Butadiene-Styrene (SBS) (60%) blend. Shape memory cycle tests are performed at different temperatures to detect the best recovery rate. Under appropriate temperature, the blend recovers substantially its original shape. To study the recovery rate evolution, multi cycle tests are realized with controlled temperature. The results indicate that the shape memory effect growths when the number of cycle increases. The stored energy acts as a driving force to bring the polymer to its permanent shape after each loading cycle. Then, an original method is proposed to measure the stress-strain evolution during the recovery. With a variable temperature, no standard test can follow the stress-strain evolution. This test is needed to validate the behavior model.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{hamdache_1579,

title = {Macroscopic limit of the kinetic Bloch equation},

author = {Kamel Hamdache and Djamila Hamroun},

url = {https://www.aimsciences.org/article/doi/10.3934/krm.2021015},

year  = {2021},

date = {2021-06-01},

journal = {Kinetic And Related Models},

volume = {14},

number = {3},

pages = {541-570},

abstract = {This work concerns the existence of solution of the kinetic spinor Boltzmann equation as well as the asymptotic behavior of such solution when ??0, that is when the time relaxation of the spin-flip collisions is very small in comparison to the time relaxation parameter of the collisions with no spin reversal. Due to the lack of regularity of the weak solution, the switching term H?×M? is not stable under the weak convergences. Hence we establish new estimates of the so},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{venkateswaran_1788,

title = {An optimal design of a flexible piping inspection robot},

author = {Swaminath Venkateswaran and Damien Charles Chablat and Pol Hamon},

url = {https://asmedigitalcollection.asme.org/mechanismsrobotics/article-abstract/13/3/035002/1096922/An-Optimal-Design-of-a-Flexible-Piping-Inspection},

year  = {2021},

date = {2021-06-01},

journal = {Journal Of Mechanisms And Robotics-Transactions Of The Asme},

volume = {13},

number = {3},

pages = {035002},

abstract = {This study presents an optimization approach for the design of a piping inspection robot. A rigid bio-inspired piping inspection robot that moves like a caterpillar was designed and developed at LS2N, France. By the addition of tensegrity mechanisms between the motor modules, the mobile robot becomes flexible to pass through the bends. However, the existing motor units prove to be oversized for passing through pipe bends at 90 deg. Thus, three cascading optimization problems are presented in this article to determine the sizing of robot assembly that can overcome such pipe bends. The first problem deals with the identification of design parameters of the tensegrity mechanism based on static stability. Followed by that, in the second problem, the optimum design parameters of the robot modules are determined for the robot assembly without the presence of leg mechanisms. The third problem deals with the determination of the size of the leg mechanism for the results of the two previous optimization problems. A digital model of the optimized robot assembly is then realized using cad software.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{chablat_1789,

title = {Workspace analysis in the design parameter space of a 2-dof spherical parallel mechanism for a prescribed workspace: Application to the otologic surgery},

author = {Damien Charles Chablat and Guillaume Michel and Philippe Bordure and Swaminath Venkateswaran and Ranjhan Jha},

url = {https://www.sciencedirect.com/science/article/pii/S0094114X20304419},

year  = {2021},

date = {2021-03-01},

journal = {Mechanism And Machine Theory},

volume = {157},

number = {3},

pages = {104224},

abstract = {During Otologic surgery, and more broadly during microsurgery, the surgeon encounters several difficulties due to the confined spaces and micro-manipulations. The purpose of the paper is to design a robot with a prescribed regular workspace shape to handle an endoscope to assist the Otologic surgery. A spherical parallel mechanism with two degrees of freedom is analysed in its design parameter space. This mechanism is composed of three legs (2USP-U) to connect the base to a moving platform connected to a double parallelogram to create a remote center of motion (RCM). Its kinematic properties, i.e. the singularity locus and the number of direct kinematic solutions, are investigated. For some design parameters, non-singular assembly modes changing trajectories may exist and have to be investigated inside the prescribed regular workspace shape. Two sets of design parameters are presented with their advantages and disadvantages.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{ben_abdallah_1269,

title = {Molecular weight influence on shape memory effect of shape memory polymer blend ( poly(caprolactone)/styrene-butadiene-styrene )},

author = {Abir Ben Abdallah and Fehmi Gamaoun and Achraf Kallel and Abbas Tcharkhtchi},

url = {https://onlinelibrary.wiley.com/doi/10.1002/app.49761},

year  = {2021},

date = {2021-02-01},

journal = {Journal Of Applied Polymer Science},

volume = {138},

number = {5},

pages = {49761},

abstract = {The shape memory effect (SME) does not only concern the macroscopic structure. It concerns also the polymer structure at morphological, macromolecular, and molecular scales. This effect may depend on different physicochemical properties like morphology heterogeneity, chain rigidity, steric hindrance, chain polarity, free volume, cross-linking or entanglement density, molecular shape and weight, and so on. Hence, finding the relationship between the SME and these properties is very important. This can help to obtain the knowledge about the phenomenon origin and mechanism. One of the basic polymer properties, which can have direct SME, may be the molecular weight (Mw). The question here is: If the Mw of a shape memory polymer (SMP) changes, for different reasons like degradation, what will be the effect of this change on its SME. In order to answer to this question, the investigation is focused on an SMP blend of 40% poly(?-caprolactone) (PCL) and 60% styrene-butadiene-styrene (SBS). Then, enzymatic hydrolysis is performed on this blend to change its Mw. It is shown that this change is only related to the variation in the Mw of PCL. After that, different samples with a distinct average Mw are prepared and characterized by various experimental methods. Shape memory tests are performed on these blends, and the recovery rate (Rr) for each of them is determined. It is found that when Mw of PCL decreases, its degree of crystallinity, its glass transition, and its melting temperatures, corresponding to the PCL phase, increase. However, the elongation at break of the blend declines with the reduction in Mw. The tests show that the alteration in the blend's Mw influences its SME. Indeed, Rr of the (PCL/SBS) mixture drops with the decrease in Mw of PCL.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pouradier_duteil_1268,

title = {Kinetic approach to the collective dynamics of the rock paper scissors binary game},

author = {Nastassia Pouradier Duteil and Francesco Salvarani},

url = {https://www.sciencedirect.com/science/article/pii/S0096300320304549#!},

year  = {2021},

date = {2021-01-01},

journal = {Applied Mathematics And Computation},

volume = {388},

pages = {125496},

abstract = {This article studies the kinetic dynamics of the rock-paper-scissors binary game. We first prove existence and uniqueness of the solution of the kinetic equation and subsequently we prove the rigorous derivation of the quasi-invariant limit for two meaningful choices of the domain of definition of the independent variables. We notice that the domain of definition of the problem plays a crucial role and heavily influences the behavior of the solution. The rigorous proof of the relaxation limit does not need the use of entropy estimates for ensuring compactness.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{zhang_1406,

title = {Failure prediction of magnesium alloys based on improved CDM model},

author = {Kai Zhang and Houssem Badreddine and Naila Hfaiedh and Khemais Saanouni and Jianlin Liu},

url = {https://www.sciencedirect.com/science/article/abs/pii/S0020768321000214?via%3Dihub},

year  = {2021},

date = {2021-01-01},

journal = {International Journal Of Solids And Structures},

volume = {217-218},

pages = {155-177},

abstract = {The aim of this contribution is to improve the behavior and failure prediction accuracy for magnesium alloy sheet forming simulation by using advanced fully coupled Continuum Damage Mechanics (CDM) model. Starting from known fully coupled constitutive equations at large inelastic (plastic or viscoplastic) strains, three aspects are enhanced on the CDM model developed by Saanouni (2012). The first one concerns the accurate description of tension-compression asymmetry in yielding and hardening of magnesium alloys induced by combined slip and twinning deformations. The second concerns introducing the stress state dependence in damage evolution to improve the fracture prediction under various loading paths. The third deals with temperature and strain rate (viscosity) effects for metal forming processes at elevated temperatures. The improved fully coupled constitutive equations were implemented into finite element code ABAQUS/Explicit via user subroutine VUMAT including the specific local integration scheme to compute the state variables at each quadrature point. Various kinds of tensile tests at different temperatures and strain rates are used to determine the material parameters, and the complete identification procedure is given in details. As validation, the improved model is applied to simulate the three-point bending and circular cup deep drawing tests, the predicted results show good agreements with the experimental observations.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{ouaddi_1582,

title = {Passive piezomagnetic monitoring of structures subjected to in-service cyclic loading: Application to the detection of fatigue crack initiation and propagation},

author = {Achraf Ouaddi and Olivier Hubert and Jader Furtado and Song He},

url = {https://doi.org/10.1063/9.0000195},

year  = {2021},

date = {2021-01-01},

journal = {Aip Advances},

volume = {11},

number = {1},

pages = {015344},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{yakoubi_1678,

title = {Analysis of a time--discrete scheme for the Navier-Stokes/Allen-Cahn model},

author = {Driss Yakoubi and Jean Deteix and G. L. Ndetchoua Kouamo},

url = {https://www.sciencedirect.com/science/article/pii/S0022247X20309793?via%3Dihub},

year  = {2021},

date = {2021-01-01},

journal = {Journal Of Mathematical Analysis And Applications},

volume = {496},

number = {2},

pages = {1-26},

abstract = {This paper address the existence and uniqueness, in suitable functional spaces, of the solution of a non linear system of equations originating from the implicit time discretization of the coupled unsteady Navier-Stokes and Allen-Cahn equations. This result is based on the convergence analysis of an original stabilized fixed point algorithm, from which we also get a maximum principle. Numerical experiments are performed to illustrate the influence of the implicit formulation in comparison to a simpler approach based on a semi-explicit time scheme.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{bobbia_1682,

title = {The coupling method in extreme value theory},

author = {Benjamin Bobbia and Clément Dombry and Davit Varron},

url = {https://arxiv.org/pdf/1912.03155.pdf},

year  = {2021},

date = {2021-01-01},

journal = {Bernoulli},

volume = {27},

number = {3},

pages = {31},

abstract = {A coupling method is developed for univariate extreme value theory, providing an alternative to the use of the tail empirical/quantile processes. We emphasize the Peak-over-Threshold approach that approximates the distribution above high threshold by the Generalized Pareto Distribution (GPD) and compare the empirical distribution of exceedances to the empirical distribution associated with the limit GPD model. Sharp bounds for their Wasserstein distance in the second order Wasserstein space are provided. As an application, we recover standard results on the asymptotic behavior of the Hill estimator, the Weissman extreme quantile estimator or the probability weighted moment estimators, shedding some new light on the theory.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{bobbia_1684,

title = {Extreme quantile regression in proportional tail framework},

author = {Benjamin Bobbia and Clément Dombry and Davit Varron},

url = {https://arxiv.org/pdf/2002.01740.pdf},

year  = {2021},

date = {2021-01-01},

journal = {Georgian Mathematical Journal},

volume = {175},

number = {1},

pages = {27},

abstract = {We revisit the model of heteroscedastic extremes initially introduced by Einmahl et al. (JRSSB, 2016) to describe the evolution of a non stationary sequence whose extremes evolve over time and adapt it into a general extreme quantile regression framework. We provide estimates for the extreme value index and the integrated skedasis function and prove their asymptotic normality. Our results are quite similar to those developed for heteroscedastic extremes but with a different proof approach emphasizing coupling arguments. We also propose a pointwise estimator of the skedasis function and a Weissman estimator of the conditional extreme quantile and prove the asymptotic normality of both estimators.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{vlad_1713,

title = {A linear benchmark between HYMAGYC, MEGA and ORB5 codes using the NLED-AUG test case to study Alfvénic modes driven by energetic particles},

author = {Gregorio Vlad and Xin Wang and Francesco Vannini and Sergio Briguglio and Nakia Carlevaro and Matteo Valerio Falessi and Giuliana Fogaccia and Valeria Fusco and Fulvio Zonca and Alessandro Biancalani and Alberto Bottino and Thomas Hayward-Schneider and Philipp Walter Lauber},

url = {https://doi.org/10.1088/1741-4326/ac2522},

year  = {2021},

date = {2021-01-01},

journal = {Nuclear Fusion},

volume = {61},

number = {1},

pages = {116026},

abstract = {One of the major challenges in magnetic confinement thermonuclear fusion research concerns

the confinement of the energetic particles (EPs) produced by fusion reactions and/or by

additional heating systems. In such experiments, EPs can resonantly interact with the shear

Alfvén waves. In the frame of the EUROfusion 2019-2020 Enabling Research project

?multi-scale energetic particle transport in fusion devices' (MET), a detailed benchmark

activity has been undertaken among few of the state-of-the-art codes available to study the

self-consistent interaction of an EP population with the shear Alfvén waves. In this paper

linear studies of EP driven modes with toroidal mode number n = 1 will be presented, in real

magnetic equilibria and in regimes of interest for the forthcoming generation devices (e.g.

ITER, JT-60SA, DTT). The codes considered are HYMAGYC, MEGA, and ORB5, the first

two being hybrid MHD-gyrokinetic codes (bulk plasma is represented by MHD equations,

while the EP species is treated using the gyrokinetic formalism), the third being a global

electromagnetic gyrokinetic code. The so-called NLED-AUG reference case has been

considered, both for the peaked on-axis and peaked off-axis EP density profile cases, using its

shaped cross section version. Comparison of the spatial mode structure, growth rate and real

frequency of the modes observed will be considered in detail. The dependence of mode

characteristics when several parameters are varied, as, e.g. the ratio between EP and bulk ion

density and EP temperature, will be presented. A remarkable agreement is observed among the

three codes for the peaked off-axis case, obtaining all of them a TAE localized close to the

magnetic axis. On the other hand, some differences are observed when considering the peaked

on-axis case, where two modes are observed (a TAE localized in the radial external region, and

an RSAE around mid-radius). A careful analysis of the stability of this equilibrium, in

particular by varying self-consistently the EP drive, will allow to reconcile the results of the

three codes.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{yakoubi_1679,

title = {Analysis of backward Euler/spectral discretization for an evolutionary mass and heat transfer in porous medium},

author = {Driss Yakoubi and Sarra Maarouf},

url = {https://www-sciencedirect-com.acces.bibl.ulaval.ca/science/article/pii/S0022247X20305898?via%3Dihub},

year  = {2020},

date = {2020-12-01},

journal = {Journal Of Mathematical Analysis And Applications},

volume = {492},

number = {1},

pages = {1-24},

abstract = {This paper presents the unsteady Darcy's equations coupled with two nonlinear reaction-diffusion equations, namely this system describes the mass concentration and heat transfer in porous media. The existence and uniqueness of the solution are established for both the variational formulation problem and for its discrete one obtained using spectral discretization. Optimal a priori estimates are given using the Brezzi-Rappaz-Raviart theorem. We conclude by some numerical tests which are in agreement with our theoretical results.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{bernard_1413,

title = {Optimal Estimate of the Spectral Gap for the Degenerate Goldstein-Taylor Model},

author = {Etienne Bernard and Francesco Salvarani},

url = {https://link.springer.com/article/10.1007/s10955-020-02631-y},

year  = {2020},

date = {2020-11-01},

journal = {Journal Of Statistical Physics},

volume = {181},

pages = {1470-1471},

abstract = {x},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{benmesbah_1563,

title = {Methane Hydrate Formation and Dissociation in Sand Media: Effect of Water Saturation, Gas Flowrate and Particle Size},

author = {Fatima Benmesbah and Livio Ruffine and Pascal Clain and Véronique Osswald and Olivia Fandino and Laurence Fournaison and Anthony Delahaye},

url = {https://www.mdpi.com/1996-1073/13/19/5200},

year  = {2020},

date = {2020-10-01},

journal = {Energies},

volume = {13},

number = {19},

pages = {5200},

abstract = {Assessing the influence of key parameters governing the formation of hydrates and determining the capacity of the latter to store gaseous molecules is needed to improve our understanding of the role of natural gas hydrates in the oceanic methane cycle. Such knowledge will also support the development of new industrial processes and technologies such as those related to thermal energy storage. In this study, high-pressure laboratory methane hydrate formation and dissociation experiments were carried out in a sandy matrix at a temperature around 276.65 K. Methane was continuously injected at constant flowrate to allow hydrate formation over the course of the injection step. The influence of water saturation, methane injection flowrate and particle size on hydrate formation kinetics and methane storage capacity were investigated. Six water saturations (10.8%, 21.6%, 33%, 43.9%, 55% and 66.3%), three gas flowrates (29, 58 and 78 mLn min?1) and three classes of particle size (80-140, 315-450 and 80-450 µm) were tested, and the resulting data were tabulated. Overall, the measured induction time obtained at 53-57% water saturation has an average value of 58 ± 14 min minutes with clear discrepancies that express the stochastic nature of hydrate nucleation, and/or results from the heterogeneity in the porosity and permeability fields of the sandy core due to heterogeneous particles. Besides, the results emphasize a clear link between the gas injection flowrate and the induction time whatever the particle size and water saturation. An increase in the gas flowrate from 29 to 78 mLn min-1 is accompanied by a decrease in the induction time up to 100 min (i.e., 77% decrease). However, such clear behaviour is less conspicuous when varying either the particle size or the water saturation. Likewise, the volume of hydrate-bound methane increases with increasing water saturation. This study showed that water is not totally converted into hydrates and most of the calculated conversion ratios are around 74-84%, with the lowest value of 49.5% conversion at 54% of water saturation and the highest values of 97.8% for the lowest water saturation (10.8%). Comparison with similar experiments in the literature is also carried out herein.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{zhang_1270,

title = {Enhanced CDM model accounting of stress triaxiality and Lode angle for ductile damage prediction in metal forming},

author = {Kai Zhang and Houssem Badreddine and Naila Hfaiedh and Khemais Saanouni and Jianlin Liu},

url = {https://journals.sagepub.com/doi/full/10.1177/1056789520958045},

year  = {2020},

date = {2020-09-01},

journal = {International Journal Of Damage Mechanics},

volume = {30},

number = {2},

pages = {260-282},

abstract = {This paper deals with the prediction of ductile damage based on CDM approach fully coupled with advanced elastoplastic constitutive equations. This fully coupled damage model is developed based on the total energy equivalence assumption under the thermodynamics of irreversible processes framework with state variables. In this model, the damage evolution is enhanced by accounting for both stress triaxiality and Lode angle. The proposed constitutive equations are implemented into Finite Element (FE) code ABAQUS/Explicit through a user material subroutine (VUMAT). The material parameters are determined by the hybrid experimental-numerical method using various tensile and shear tests. Validation of the proposed model has been done using different tests of two aluminum alloys (Al6061-T6 and Al6014-T4). Through comparisons of numerical simulations with experimental results for different loading paths, the predictive capabilities of the proposed model have been shown. The model is found to be able to capture the initiation as well as propagation of macro-crack in sheet and bulk metals during their forming processes},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{hamroun_1169,

title = {Existence of large solutions to the Landau-Lifshitz-Bloch equation},

author = {Djamila Hamroun and Kamel Hamdache},

url = {https://www.intlpress.com/site/pub/pages/journals/items/cms/_home/acceptedpapers/index.php},

year  = {2020},

date = {2020-05-14},

journal = {Communications In Mathematical Sciences},

volume = {18},

number = {2},

pages = {487-513},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{hamdache_606,

title = {Weak Solutions to Unsteady and Steady Models of Conductive Magnetic Fluids},

author = {Kamel Hamdache and Djamila Hamroun},

url = {https://link.springer.com/article/10.1007%2Fs00245-018-9505-x},

year  = {2020},

date = {2020-04-01},

journal = {Applied Mathematics And Optimization},

volume = {81},

pages = {479-509},

abstract = {We study a nonlinear coupling system of partial differential equations describing the dynamic of a magnetic fluid with internal rotations. The present mathematical model generalizes those discussed previously in the literature since actually the fluid is electrically conducting inducing additional nonlinearities in the problem and the dynamics of the magnetic field is described by the quasi-static Maxwell equations instead of the usual magnetostatic ones. We prove existence of weak solutions with finite energy first for the unsteady problem then for the steady one.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{yakoubi_1680,

title = {A projection scheme for Navier--Stokes with  variable viscosity and natural boundary condition},

author = {Driss Yakoubi and Ludovic Plasman and Jean Deteix},

url = {https://onlinelibrary-wiley-com.acces.bibl.ulaval.ca/doi/epdf/10.1002/fld.4851},

year  = {2020},

date = {2020-04-01},

journal = {International Journal for Numerical Methods in Fluids},

volume = {92},

number = {12},

pages = {1-21},

abstract = {Combiningthe Navier-Stokes systems with Neumann (or natural) boundary condition to characterize a fluid flow is frequent. The popular projection (or pressure

correction) methods inspired by Chorin and Temam are not well adapted to such boundary condition, which translate in loss of accuracy. If some alternative projection methods have been proposed to reduce the accuracy loss due to the Neumann condition in case of Newtonian fluids, little has been pro-

posed for generalized Newtonian fluids. In this work, we propose two methods

derived from the incremental pressure correction projection that can be used

for fluids with inhomogeneous or variable viscosity with natural boundary condition. Both time and space accuracy of the methods will be illustrated using a manufactured solution.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{anwasia_1125,

title = {On the Maxwell- Stefan diffusion limit for reactive mixture of polyatomic gases in non-isothermal setting},

author = {Benjamin Anwasia and Marzia Bisi and Ana Jacinta Soares and Francesco Salvarani},

url = {https://www.aimsciences.org/article/doi/10.3934/krm.2020003},

year  = {2020},

date = {2020-02-01},

journal = {Kinetic And Related Models},

volume = {13},

number = {1},

pages = {63-95},

abstract = {In this article we deduce a mathematical model of Maxwell-Stefan type for a reactive mixture of polyatomic gases with a continuous structure of internal energy. The equations of the model are derived in the diffusive limit of a kinetic system of Boltzmann equations for the considered mixture, in the general non-isothermal setting. The asymptotic analysis of the kinetic system is performed under a reactive-diffusive scaling for which mechanical collisions are dominant with respect to chemical reactions. The resulting system couples the Maxwell-Stefan equations for the diffusive fluxes with the evolution equations for the number densities of the chemical species and the evolution equation for the temperature of the mixture. The production terms due to the chemical reaction and the Maxwell-Stefan diffusion coefficients are moreover obtained in terms of general collision kernels and parameters of the kinetic model.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{mula_1514,

title = {Homogenization in the energy variable for a neutron transport model.},

author = {Olga Mula and Francesco Salvarani and Harsha Hutridurga},

url = {https://content.iospress.com/articles/asymptotic-analysis/asy191544},

year  = {2020},

date = {2020-01-01},

journal = {Asymptotic Analysis},

volume = {117},

number = {1-2},

pages = {1-25},

abstract = {This article addresses the homogenization of linear Boltzmann equation when the optical parameters are highly heterogeneous in the energy variable. We employ the method of two-scale convergence to arrive at the homogenization result. In doing so, we show the induction of a memory effect in the homogenization limit. We also provide some numerical experiments to illustrate our results. In the Appendix, we treat a related case of the harmonic oscillator.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{charles_1518,

title = {Mathematical and numerical study of a dusty Knudsen gas mixture},

author = {Frédérique Charles and Francesco Salvarani},

url = {https://link.springer.com/article/10.1007/s10440-019-00277-x},

year  = {2020},

date = {2020-01-01},

journal = {Acta Applicandae Mathematicae},

volume = {168},

number = {1},

pages = {17-31},

abstract = {We consider a mixture composed of a gas and dust particles in a very rarefied setting. Whereas the dust particles are individually described, the surrounding gas is treated as a Knudsen gas, in such a way that interactions occur only between gas particles and dust by means of diffuse reflection phenomena. After introducing the model, we prove the existence and the uniqueness of the solution and provide a numerical strategy for the study of the equations. At the numerical level, we focus our attention on the phenomenon of energy transfer between the gas and the moving dust particles.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}