СЕМИНАР ПО МЕХАНИКЕ СПЛОШНЫХ СРЕД

Уважаемые коллеги!

В среду, 12 декабря 2018 г., в кинозале Института механики МГУ в 12.00 состоится очередное заседание семинара по механике сплошных сред под руководством А.Г. Куликовского, В.П. Карликова и О.Э. Мельника.

Philippe Fraunié

Mediterranean Institute of Oceanography, Université de Toulon, Aix Marseille Université, CNRS, IRD

OCCURENCE OF HYDRODYNAMICAL INSTABILITIES IN NON PARALLEL FLOWS

From Direct Numerical Simulation using spectral element methods, several classical flows instabilities are analyzed as the Blasius Boundary layer, first and second Hopf bifurcation of cylinder wakes, plan and round jets and the Ekman spiral. A time decomposition technique allows to evidence the dominant modes of occurring instabilities in full Navier-Stokes equations with a good agreement with experimental data and contemporary usual numerical simulations.

Moreover, from Large Eddy Simulatons, persistence of coherent structures in turbulent homogeneous and stratified flows is investigated in a range a parameters. Especially, layering effect as observed both in stable ocean and atmosphere has been investigated and results confirm Park et al theory. Several numerical techniques including high order compact discretization and dedicated boundary conditions are developed to improve accuracy and efficiency of numerical models to describe fine structures as observed in laboratory experiments.

Theoretical, measurement and numerical tools are discussed in terms of limitations and complementarity for a better understanding of instabilities and persistent coherent structures.