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DY: Fachverband Dynamik und Statistische Physik

DY 33: Fluid Dynamics and Turbulence

DY 33.4: Talk

Wednesday, March 22, 2017, 10:45–11:00, ZEU 160

Multi-Scale Analysis of Lagrangian Properties of Turbulence — •Michael Wilczek and Cristian Lalescu — Max-Planck-Institut für Dynamik und Selbstorganisation, Göttingen, Deutschland

Turbulence is a multi-scale problem in space and time with a broad range of strongly interacting degrees of freedom. Lagrangian tracer particles advected with the flow sample this spatio-temporal complexity. This naturally leads to the question of how Lagrangian properties are affected by the scales of turbulence. We attempt to answer this question numerically and theoretically adopting a filtering approach. In an extensive DNS (direct numerical simulation) study, we track tracer particles advected by spatially filtered velocity fields. This allows to distinguish the impact of large-scale sweeping effects and small-scale intermittency on Lagrangian aspects of turbulence. In this presentation we will present results on Lagrangian particle dispersion and velocity fluctuations for various filtering scales. The results will furthermore be discussed in the context of Eulerian-Lagrangian bridging relations.