The equation for the intrinsic moment of momentum averaged over small volumes of linear dimension delta has been considered. A representation of it is given as an infinite sequence of independent equations using a series expansion in terms of delta(2). The equations of different orders are obtained through linear antisymmetric operators-with a structure that is similar to that of the curl-acting on the momentum equation. The first-order term of the sequence is the Helmholtz equation; the remaining terms can be considered as balances for a kind of higher-orders vorticity. It has been shown that the coupling between the momentum and the angular momentum equation, based on a supposed antisymmetrical part of the stress tensor-which has sometimes been assumed by authors who deal with turbulent flow of a homogeneous fluid-is devoid of physical rationale. A different form of coupling is proposed that may be used to describe a turbulent flow of a homogeneous medium, using a large eddy simulation technique. In the authors model the coupling is given by a functional dependence of the turbulent eddy diffusivity over the angular momentum of a finite volume of a fluid.

The angular momentum equation for a finite element of fluid: a new representation and application to turbulent modeling / Iovieno, Michele; Tordella, Daniela. - In: PHYSICS OF FLUIDS. - ISSN 1070-6631. - STAMPA. - 14:8(2002), pp. 2673-2682. [10.1063/1.1485765]

The angular momentum equation for a finite element of fluid: a new representation and application to turbulent modeling

IOVIENO, MICHELE;TORDELLA, Daniela
2002

Abstract

The equation for the intrinsic moment of momentum averaged over small volumes of linear dimension delta has been considered. A representation of it is given as an infinite sequence of independent equations using a series expansion in terms of delta(2). The equations of different orders are obtained through linear antisymmetric operators-with a structure that is similar to that of the curl-acting on the momentum equation. The first-order term of the sequence is the Helmholtz equation; the remaining terms can be considered as balances for a kind of higher-orders vorticity. It has been shown that the coupling between the momentum and the angular momentum equation, based on a supposed antisymmetrical part of the stress tensor-which has sometimes been assumed by authors who deal with turbulent flow of a homogeneous fluid-is devoid of physical rationale. A different form of coupling is proposed that may be used to describe a turbulent flow of a homogeneous medium, using a large eddy simulation technique. In the authors model the coupling is given by a functional dependence of the turbulent eddy diffusivity over the angular momentum of a finite volume of a fluid.
2002
File in questo prodotto:
Non ci sono file associati a questo prodotto.
Pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11583/1406605
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo