Intermittency layers associated to turbulent interfaces

Tipo di pubblicazione: Articolo in atti di convegno
Tipologia MIUR: Contributo in Atti di Convegno (Proceeding) > Abstract in atti di convegno
Titolo: Intermittency layers associated to turbulent interfaces
Autori: Iovieno M., Di Savino S., De Santi F., Tordella D.
Autori di ateneo:
Tipo di referee: Comitato scientifico
Titolo del convegno: EFMC9 - 9th European Fluid Mechanics Conference
Luogo dell'evento: Roma (I)
Data dell'evento: 9-13 September 2012
Rilevanza dell'evento: Internazionale
Abstract: In this study we focus on the transport across an interface which separates two regions with homogeneous and isotropic turbulence in absence of a mean shear. The turbulent transport resulting presents an internal structure. Indeed, in the case of turbulent self-diffusion, both experiments and simulations show that the fluid velocity field is marked by a high intermittency front located aside the interface, which is the source of turbulent bursts penetrating the low turbulence region. The presence of an inner structure inside a layer of turbulence self-transport highlights the different nature of the turbulent transport with respect to the Gaussian diffusion. By including other effects, for instance a passive scalar transport or a mass transport in presence of a density stratification, the phenomenology is much enriched. For instance, our preliminary numerical experiments on the passive scalar transport reveals the presence of two intermittency fronts, one on each side of the interface. As can be seen if the figure below, the intermittency level in the fronts is high. This is true both for the scalar and the scalr derivative statistics. A gradual decay in time is observed while they propagate toward the lateral isotropic regions of the flow. In the presence of a kinetic energy gradient across the interface, the locations and intensity of the intermittency fronts are no more symmetric to respect to the interface. The front on the high energy side of the mixing region penetrates deeper and exhibits stronger intermittency. Analogous features are observed also in two dimensions
Data: 2012
Status: Pubblicato
Lingua della pubblicazione: Inglese
Parole chiave: intermittency, passive scalar, turbulent transport
Dipartimenti (originale): DIMEAS - Dipartimento di Ingegneria Meccanica e Aerospaziale
Dipartimenti: DIMEAS - Dipartimento di Ingegneria Meccanica e Aerospaziale
DISAT - Dipartimento Scienza Applicata e Tecnologia
URL correlate:
Area disciplinare: Area 09 - Ingegneria industriale e dell'informazione > FLUIDODINAMICA
Data di deposito: 29 Ott 2012 16:36
Data ultima modifica (IRIS): 26 Feb 2015 18:05:54
Data inserimento (PORTO): 30 Mar 2016 05:11
Permalink: http://porto.polito.it/id/eprint/2503403
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