Difference between revisions of "Sig Turbulence / Flow over Periodic Hills"
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* [[Sig Turbulence / 2D backward-facing step |2D backward-facing step]] : it's a quick test case because of it's a 2D model but the separation bubble is determined by the spet geometry. | * [[Sig Turbulence / 2D backward-facing step |2D backward-facing step]] : it's a quick test case because of it's a 2D model but the separation bubble is determined by the spet geometry. | ||
* [[Sig Turbulence / Asymmetric diffuser |Asymmetric diffuser]] : we know experimental's data which was made by Buice and Eaton [[http://www.grc.nasa.gov/WWW/wind/valid/buice/buice02/buice02.html]]. Unfortunatly, the Reynolds number of the fow was necessarily slow (<math> Re_{\tau} = 180 </math>). | * [[Sig Turbulence / Asymmetric diffuser |Asymmetric diffuser]] : we know experimental's data which was made by Buice and Eaton [[http://www.grc.nasa.gov/WWW/wind/valid/buice/buice02/buice02.html]]. Unfortunatly, the Reynolds number of the fow was necessarily slow (<math> Re_{\tau} = 180 </math>). | ||
| − | * [[Sig Turbulence / Periodic | + | * [[Sig Turbulence / Flow over Periodic Hill |Periodic hill]] : we know experimental's data which was made by Almeida et al. [1] but in Mellen and al. [2] et Temmerman et al. [3] we can find that they have an influence of the side wall so the 1995 ERCOFTAC/IAHR workshop have cast a doubt on the true periodicity of the experimental configuration. But we have some data from LES with a good mesh like [[http://cfd.mace.manchester.ac.uk/cgi-bin/cfddb/prpage.cgi?81&LES&database/cases/case81/Case_data&database/cases/case81&cas81_head.html&cas81_desc.html&cas81_meth.html&cas81_data.html&cas81_refs.html&cas81_rsol.html&1&1&1&1&1&unknown]] |
The probleme of this flow is the separtion bubble which is due to a adverse pressure gradient that's why this is a test case for many subgrid scale models (SGS) and for near-wall low. | The probleme of this flow is the separtion bubble which is due to a adverse pressure gradient that's why this is a test case for many subgrid scale models (SGS) and for near-wall low. | ||
Revision as of 07:17, 29 May 2009
Olivier Brugiere, Universite Joseph Fourier, Grenoble, France
Contents
1 Motivation
The flow over bodies with massive separation constitutes an important area of applications for LES. In many geometrie we can find this kind of flow like the 2D backward-facing step, the asymmetric diffuser or the periodic hill.
- 2D backward-facing step : it's a quick test case because of it's a 2D model but the separation bubble is determined by the spet geometry.
- Asymmetric diffuser : we know experimental's data which was made by Buice and Eaton [[1]]. Unfortunatly, the Reynolds number of the fow was necessarily slow (
).
- Periodic hill : we know experimental's data which was made by Almeida et al. [1] but in Mellen and al. [2] et Temmerman et al. [3] we can find that they have an influence of the side wall so the 1995 ERCOFTAC/IAHR workshop have cast a doubt on the true periodicity of the experimental configuration. But we have some data from LES with a good mesh like [[2]]
The probleme of this flow is the separtion bubble which is due to a adverse pressure gradient that's why this is a test case for many subgrid scale models (SGS) and for near-wall low.
2 Testcase description and numerical results
2.1 Flow configuration
Flow over 2D periodic is in fact an experimental configuration with 9 hills. For the computational, we represent this configuration by a channel periodic with two half's hills like on the next figure :
2.2 Geometrical Parameters
2.3 Simulation details
3 References
[1] Almeida, Durao and Heitor , 1993, Experimental thermal and fluid science, Vol. 7, pp. 87-101.
[2] Mellen, Frohlich, Rodi , 2000, Large Eddy Simulation of the flow over periodic hills, 16th IMACS World Congress , Lausanne.
[3] Temmerman, Leschziner , 2001, Large Eddy Simulation of separated flow in a streamwise periodic channel construction, Int. Symp. on Turbulence and Shear Flow Phenomena, Stockholm, June 27-29.
