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A modification of DDES based on a detection of attached boundary layers and flow separation

Knopp, Tobias (2010) A modification of DDES based on a detection of attached boundary layers and flow separation. 17. DGLR-Fach-Symposium der STAB, 09.-10. Nov. 2010, Berlin, Deutschland.

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Official URL: http://www.dlr.de/as/desktopdefault.aspx/tabid-652/1104_read-1678/


We present a new hybrid RANS-LES method of DDES-type for flows with small/incipient separation. It alters the RANS-LES switch based on the function f_d in the DDES formulation. Instead we present a method for detecting regions of attached boundary layer flow, the separation point and the subsequent region of separation, developed for flows over airfoil sections. This method is based on a combination of algebraic properties of the mean velocity profiles in wall-normal direction inspired by Stock&Haase (1987) and of integral boundary layer quantities, namely the shape factor H. Then the RANS length scale l_RANS is used in attached boundary layers. The LES length scale C_DES*Delta is used in regions of separated flow. In particular, thin regions of (incipiently) separated flow are treated in LES mode except for a near-wall region where l_RANS is used. Moreover, in the vicinity of the separation point or in the entire separation region, a stochastic SGS model is used as a simple method to force the generation of turbulent content.

Item URL in elib:https://elib.dlr.de/67080/
Document Type:Conference or Workshop Item (Speech, Paper)
Title:A modification of DDES based on a detection of attached boundary layers and flow separation
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Refereed publication:No
Open Access:Yes
Gold Open Access:No
In ISI Web of Science:No
Series Name:STAB-Mitteilung
Keywords:Detached-eddy simulation; incipient separation; separation; shape factor
Event Title:17. DGLR-Fach-Symposium der STAB
Event Location:Berlin, Deutschland
Event Type:national Conference
Event Dates:09.-10. Nov. 2010
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Aeronautics
HGF - Program Themes:Aircraft Research (old)
DLR - Research area:Aeronautics
DLR - Program:L AR - Aircraft Research
DLR - Research theme (Project):L - Concepts & Integration (old)
Location: Göttingen
Institutes and Institutions:Institute of Aerodynamics and Flow Technology > CASE
Deposited By: Knopp, Dr.rer.nat. Tobias
Deposited On:21 Dec 2010 12:49
Last Modified:31 Jul 2019 19:29

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