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A new extension for k-omega turbulence models to account for wall roughness

Knopp, Tobias and Eisfeld, Bernhard and Bartolome Calvo, Javier (2009) A new extension for k-omega turbulence models to account for wall roughness. International Journal of Heat and Fluid Flow, 30 (1), pp. 54-65. Elsevier. DOI: 10.1016/j.ijheatfluidflow.2008.09.009

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Abstract

This paper presents a new extension for k-omega turbulence models to account for surface roughness for transitionally and fully rough surfaces. It is based on the equivalent sand grain approach and accounts for theoretical considerations on the log-layer solution for fully rough surfaces. An appropriate behaviour for transitional roughness is achieved by means of wall values for k and omega which depend on the roughness Reynolds number. In the limit of vanishing roughness, the smooth wall boundary condition is recovered. For the full range of roughness Reynolds numbers the new roughness modification gives very successful predictions for a variety of flat plate turbulent boundary layer flows and for the pipe flow experiments by Nikuradse. The new method allows for the simulation of flows over rough surfaces at the same grid resolution requirements as for smooth walls. Thereby the extremely fine near-wall mesh resolution required by the Wilcox roughness modification is avoided. Secondly the new roughness modification gives significantly improved predictions in skin friction for transitional roughness Reynolds numbers compared to the roughness extension by Wilcox. Thirdly, the new roughness extension does not require a modification of the SST k-omega model, whereas a modification is necessary if the roughness extension by Wilcox is used. Finally the new method is applied successfully to predict the aerodynamic effects of surface roughness on the flow past an airfoil in highlift conditions.

Item URL in elib:https://elib.dlr.de/61452/
Document Type:Article
Title:A new extension for k-omega turbulence models to account for wall roughness
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Knopp, TobiasDLR ASUNSPECIFIED
Eisfeld, BernhardDLR ASUNSPECIFIED
Bartolome Calvo, JavierDLR ASUNSPECIFIED
Date:2009
Journal or Publication Title:International Journal of Heat and Fluid Flow
Refereed publication:Yes
Open Access:No
Gold Open Access:No
In SCOPUS:Yes
In ISI Web of Science:Yes
Volume:30
DOI :10.1016/j.ijheatfluidflow.2008.09.009
Page Range:pp. 54-65
Publisher:Elsevier
Status:Published
Keywords:Boundary layer; Turbulence modelling; Wall roughness; Equivalent sand grain; Skin friction
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:other
HGF - Program Themes:other
DLR - Research area:Aeronautics
DLR - Program:L - no assignment
DLR - Research theme (Project):L - no assignment (old)
Location: Braunschweig , Göttingen
Institutes and Institutions:Institute of Aerodynamics and Flow Technology > CASE
Deposited By: Knopp, Dr.rer.nat. Tobias
Deposited On:07 Dec 2009 10:45
Last Modified:06 Sep 2019 15:26

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