The paper describes the energy fluxes simultaneously occurring in the space of scales and in the physical space of wall-turbulent flows. The unexpected behavior of the en- ergy fluxes consists of spiral-like paths in the combined physical/scale space where the controversial reverse energy cascade plays a central role. Two dynamical processes are identified as driving mechanisms for the fluxes, one in the near wall region and a second one further away from the wall. The former, stronger one is related to the dynamics involved in the near-wall turbulence regeneration cycle. The second suggests an outer self-sustaining mechanism which is asymptotically expected to take place in the even- tual log-layer and could explain the debated mixed inner/outer scaling of the near-wall statistics. The observed behavior may have strong repercussions on both theoretical and modeling approaches to wall-turbulence, as anticipated by a simple equation which is shown able to capture most of the rich dynamics of the shear dominated region of the flow.

Paths of energy in turbulent channel flows / A. Cimarelli; E. De Angelis; C.M. Casciola. - In: JOURNAL OF FLUID MECHANICS. - ISSN 0022-1120. - STAMPA. - 715:(2013), pp. 436-451. [10.1017/jfm.2012.528]

Paths of energy in turbulent channel flows

CIMARELLI, ANDREA;DE ANGELIS, ELISABETTA;
2013

Abstract

The paper describes the energy fluxes simultaneously occurring in the space of scales and in the physical space of wall-turbulent flows. The unexpected behavior of the en- ergy fluxes consists of spiral-like paths in the combined physical/scale space where the controversial reverse energy cascade plays a central role. Two dynamical processes are identified as driving mechanisms for the fluxes, one in the near wall region and a second one further away from the wall. The former, stronger one is related to the dynamics involved in the near-wall turbulence regeneration cycle. The second suggests an outer self-sustaining mechanism which is asymptotically expected to take place in the even- tual log-layer and could explain the debated mixed inner/outer scaling of the near-wall statistics. The observed behavior may have strong repercussions on both theoretical and modeling approaches to wall-turbulence, as anticipated by a simple equation which is shown able to capture most of the rich dynamics of the shear dominated region of the flow.
2013
Paths of energy in turbulent channel flows / A. Cimarelli; E. De Angelis; C.M. Casciola. - In: JOURNAL OF FLUID MECHANICS. - ISSN 0022-1120. - STAMPA. - 715:(2013), pp. 436-451. [10.1017/jfm.2012.528]
A. Cimarelli; E. De Angelis; C.M. Casciola
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/134673
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