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15 mins
Energy flux in isotropic turbulence under large variations of external forcing
Haitao Xu, Fabio Di Lorenzo, Alain Pumir, Eberhard Bodenschatz
Session: Large Eddy Simulation 2
Session starts: Thursday 27 August, 15:00
Presentation starts: 16:00
Room: Room E

Haitao Xu ()
Fabio Di Lorenzo ()
Alain Pumir ()
Eberhard Bodenschatz ()

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.