A physical length-scale for LES of turbulent flow

Autor:	Piomelli, Ugo, Geurts, B.J., Kuerten, Hans, Geurts, Bernard, Armenio, Vincenzo, Fröhlich, Jochen
Jazyk:	angličtina
Rok vydání:	2011
Předmět:	Physics Length scale Scale (ratio) Turbulence Turbulence modeling Grid Eddy viscosity Physics::Fluid Dynamics Filter (large eddy simulation) Integral scale Eddy Aliasing Smagorinsky model Statistical physics Plane channel Integral length scale
Zdroj:	ERCOFTAC Series ISBN: 9789400724815 Direct and Large-Eddy Simulation VIII, 15-20 STARTPAGE=15;ENDPAGE=20;TITLE=Direct and Large-Eddy Simulation VIII
ISSN:	1382-4309
DOI:	10.1007/978-94-007-2482-2_3
Popis:	The fundamental assumption underlying large-eddy simulations (LES) is that the large, energy-carrying, eddies are resolved, while only the smaller eddies are modeled. An implication of this assumption is that the filter-width Δ, the length scale that separates the resolved from the unresolved eddies, should be a fraction of the integral scale, which is characteristic of the large eddies. In practice, however, the filter width is taken to be proportional to the grid size, h. This approach is generally legitimate, since the grid is usually refined where the important turbulence scales are smaller; it presents, however, two problems. First, rapid variations of the mesh (especially in methods that use local mesh refinement) may cause commutation and aliasing errors, and unphysical results (Vanella et al., 2008). Second, it requires knowledge, on the part of the user, on the characteristics of turbulence; in complex flows it may not be possible to predict the turbulence behavior a priori.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_dedup___::7113f3fd2f3ba4c7c0aa2c9d650263d9 https://doi.org/10.1007/978-94-007-2482-2_3 Zobrazit plný text záznamu