Modélisation numérique du mélange turbulent en géométrie confinée / Numerical modeling of turbulent mixing in confined geometries

Résumé Francais : cf. résumé en anglais.

Résumé Anglais : The numerical simulation of mixing in laminar and turbulent flows has many applications, for example for the prediction of pollutants in the atmosphere or in the sea. The aim of this thesis project is to study the mixing of passive scalars and point particles in confined vessels by means of numerical simulation using different mixing devices, e.g. a moving rod. An existing code for solving incompressible Navier- Stokes and advection-diffusion equations with no-slip and no-flux boundary conditions for the velocity and the passive scalar, respectively, is used on massively parallel supercomputers. The boundary conditions are imposed on the wall and the rod by using a volume penalization method while the Navier-Stokes solver used a pseudospectral discretization. Various configurations should be studied and the mixing properties should be quantified for different Reynolds and Schmidt numbers. Comparisons with available experiments should also be performed. Moreover, the Lagrangian statistics of particles will be studied using advanced analysis tools, like directional multiscale statistics and wavelet decompositions. References: [1] B. Kadoch, D. Kolomenskiy, Ph. Angot and K. Schneider. A volume penalization method for incompressible flows and scalar advection-diffusion with moving obstacles. J. Comput. Phys., 231, 4365-4383, 2012. [2] B. Kadoch, W.J.T. Bos and K. Schneider. The influence of walls on Lagrangian statistics in two-dimensional turbulence. Phys. Fluids, 23, 085111, 2011. [3] W.J.T. Bos, B. Kadoch and K. Schneider. Angular multiscale statistics of Lagrangian trajectories in turbulence. Preprint, 11/2014, http://hal.archives-ouvertes.fr/hal-01085070 [4] K. Schneider and O. Vasilyev. Wavelet methods in computational fluid dynamics. Annu. Rev. Fluid Mech., 42, 473-503, 2010.

Débouchés : Recherche académique ou privée