Lagrangian study of the inhomogeneity and unsteadiness in turbulent thermal convection
O. Liot, A. Gay, D. Martin-Calle, J. Salort, M. Bourgoin, F. Chillà
Although the Lagrangian approach is well developed since one decade to explore turbulent flows, few studies have been proposed in turbulent convection. We propose an experimental Lagrangian study (by tracking hundreds of sub-millimetric particles) in a large volume of a convection cell where a fraction of the Large Scale Circulation (LSC) can be captured. The flow inhomogeneity has a large impact on the velocity distributions. By removing the mean flow we are able to study turbulent convection unsteadiness such as sloshing of the LSC. Furthermore we observe that the dispersion of particles pairs is also highly a ected by the inhomogeneous mean flow and can be easily modelled.