Hello there! My name is Lucien and welcome to my website. I completed my Ph.D. thesis at the end of 2019, afterward I worked as a postdoctoral researcher at the LMFA laboratory. I now continue my research as postdoctoral reasearcher at Centre Européen de Recherche et de Formation Avancée en Calcul Scientifique (CERFACS). My research interests include fluid dynamics, lattice Boltzmann method, multi-species diffusion, kinetic theory, and physical oceanography. You will find some posts about my research and links to my articles.
Besides my research, I can’t decide between the seaside and the mountainside enjoying windsurfing, sailing, as well as hiking, and mountain biking.
PhD. student in Fluid mechanics, 2016-2019
Consevatoire National des Arts et Métiers / DynFluid laboratory
MSc. student in Numerical mechanics (dual master's degree), 2015-2016
Université Côte d'Azur
MSc. student in Fluid mechanics and Marine engineering, 2013-2016
SeaTech school of engineering
Numerical simulations aim to represent the real-world dynamics of a physical system with the help of a computer. Despite being an …
Viscous fingering is an ubiquitous instability that occurs when a less viscous fluid displaces a more viscous fluid in a porous medium. …
In nature, chemical compounds commonly mix each other. One of the elemental material in fluid mechanics, air, is predominantly composed …
The motivation of this study is twofold. First, a recursive mathematical formulation of the discrete-velocity Boltzmann equation (DVBE) under the Bhatnagar-Gross-Krook (BGK) approximation is introduced. This formulation allows us to formally express the solution of the DVBE as an infinite sum over successive particle derivatives of the distributions associated with local equilibrium. A Chapman-Enskog multiple-scales expansion shows that this sum can be safely truncated beyond the second order if the Navier-Stokes level of description is requested. Therefore, the distribution functions depend only on the first and second-order derivatives of the related equilibrium distributions. This alternative equation to the DVBE defines a basis to design kinetic schemes for the evolution of the distribution functions based solely on flow variables that are sufficient to define local equilibrium. Second, a family of mass-conserving numerical schemes is introduced from this kinetic equation by discretizing the particle derivatives by backward finite differences. Interestingly, a so-called “simplified Lattice Boltzmann method” introduced by Chen et al. in 2017 can be recast in this family. Numerical simulations highlight a level of numerical dissipation that is generally higher than the level obtained with a standard Lattice Boltzmann scheme, as expected by approximating derivatives by finite differences. Nevertheless, we show by using a von Neumann analysis that it is possible to parametrize our scheme, according to the relaxation coefficient of the DVBE, to reduce significantly its numerical dissipation and improve its spectral properties. We believe that this modeling can also be of interest to connect macroscopic and kinetic representations, e.g. when dealing with initial and boundary conditions or in hybrid simulations matching Navier-Stokes and Lattice Boltzmann schemes.
A lattice Boltzmann method for miscible gases is presented. In this model, the standard lattice Boltzmann method is employed for each species composing the mixture. Diffusion interaction among species is taken into account by means of a force derived from kinetic theory of gases. Transport coefficients expressions are recovered from the kinetic theory. Species with dissimilar molar masses are simulated by also introducing a force. Finally, mixing dynamics is recovered as shown in different applications: an equimolar counterdiffusion case, Loschmidt’s tube experiment, and an opposed jets flow simulation. Since collision is not altered, the present method can easily be introduced in any other lattice Boltzmann algorithms.
In the first part of the presentation, we introduce a lattice Boltzmann model for miscible gases. In this model, the standard lattice …
2020-2021
2017-2019