15th European Turbulence Conference 2015
August 25-28th, 2015, Delft, The Netherlands
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Energy flux in isotropic turbulence under large variations of external forcing


Go-down etc15 Tracking Number 315

Presentation:
Session: Large Eddy Simulation 2
Room: Room E
Session start: 15:00 Thu 27 Aug 2015

Haitao Xu   hxu1@gwdg.de
Affifliation:
Fabio Di Lorenzo   fabio.dilorenzo@ds.mpg.de
Affifliation:
Alain Pumir   alain.pumir@ds.mpg.de
Affifliation:
Eberhard Bodenschatz   eberhard.bodenschatz@ds.mpg.de
Affifliation:

Topics: - Intermittency and scaling, - Large eddy simulation and related techniques

Abstract:

We investigate the response of energy flux in isotropic turbulence to step-function like perturbation in external forcing at large length scales. From both physical experiments and direct numerical simulations, we measured the evolution of the Eulerian velocity structure functions, such as $D_{LL}(r)$, $D_{NN}(r)$, before and after the perturbation in forcing. In both cases, we observed the cascade of the energy excess at large scales cascade through scales to the dissipative range, which can be used to study the dynamics of the cascade, and in particular, to estimate the relevant time scales.