Regensburg 2016 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 57: Focus Session: Turbulence - From Pattern Formation to Stochastic Disorder

DY 57.10: Talk

Thursday, March 10, 2016, 17:45–18:00, H46

Quantifying non-locality in fully developed incompressible turbulence — •Dimitar Vlaykov and Michael Wilczek — MPI for Dynamics and Self-Organisation, Goettingen, Germany

The complexity of turbulence flows is deeply rooted in the non-locality of the governing Navier-Stokes equations. The latter can be understood as the formal dependence of even the short-term evolution of a fluid element on the state of the entire system. In incompressible hydrodynamics, the Navier-Stokes equations encode this through the kinematic pressure gradient. The pressure is determined by a Poisson relation sourced by the difference between the squared rate-of-strain and the enstrophy. This links the non-local pressure to the small-scale topology of the flow.

In this presentation we aim at quantifying the nature and the range of the pressure contributions. In particular, we attempt to characterize the neighbourhood, which contains the governing part of the contributions, via a statistical analysis of a sequence of sub-domains of increasing size. Additionally, we consider the link between the small-scale structure topology and the destructive interference between vortices and strain sheets.