Berlin 2018 – scientific programme
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DY: Fachverband Dynamik und Statistische Physik
DY 42: Turbulence
DY 42.3: Talk
Wednesday, March 14, 2018, 10:30–10:45, BH-N 128
Filtered kinetic energy budget in two-dimensional Rayleigh-Bénard convection — •Gerrit Green1,2, Dimitar Vlaykov1, Juan-Pedro Mellado3, and Michael Wilczek1 — 1Max-Planck-Institute for Dynamics and Self-Organization, Göttingen, Germany — 2Georg-August-University Göttingen — 3Max-Planck-Institute for Meteorology, Hamburg, Germany
The dynamics of turbulent Rayleigh-Bénard convection (RBC) exhibits a complex interaction between coherent large-scale flow patterns, so-called superstructures, and small-scale fluctuations. It is largely unexplained how such superstructures trigger small-scale turbulence and, conversely, how turbulence sustains or inhibits superstructures. In this contribution, we employ two-dimensional direct numerical simulations to investigate the interaction between scales. A filtering approach is used to separate the large and small scales. This allows us to systematically study the distinct contributions to the large-scale kinetic energy budget. Different Rayleigh and Prandtl numbers are explored with this method. We show that most of the energy tranfer between scales occurs near the wall and that in the bulk it is approximately independent of height. The ultimate goal is to find an effective description of turbulent superstructures in RBC, and the presented results will help to understand how to establish such a description.