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 / Flow over Periodic Hills |Periodic Hills]] : 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]] | + | [[Image:hilloutlined.jpg|thumb|Figure 1 : periodic hill]] |
| + | * [[Sig Turbulence / Flow over Periodic Hills |Periodic Hills]] : 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]]. 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 figure 1. | ||
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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. | ||
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=== Flow configuration === | === Flow configuration === | ||
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==== Geometrical Parameters ==== | ==== Geometrical Parameters ==== | ||
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=== Simulation details === | === Simulation details === | ||
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| + | [[File:Hill_mesh.jpg|thumb|Figure 2 : Hill mesh]] | ||
We have make the geometry on Gambit Fig 2 and the mesh is composed by <math>Nx \times Ny \times Nz = 118 \times 33 \times96</math>. | We have make the geometry on Gambit Fig 2 and the mesh is composed by <math>Nx \times Ny \times Nz = 118 \times 33 \times96</math>. | ||
| − | + | The aim of my study is testing a posteriori near-wall low. To compare we are running three case : | |
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| + | ** With near-wall low | ||
| + | ** With the Spalding Low [5] | ||
| + | ** Wiht the Mahart et al. low [6] | ||
== Numerical results == | == Numerical results == | ||
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== References == | == References == | ||
| − | [1] Almeida, Durao and Heitor , 1993, Experimental thermal and fluid science, Vol. 7, pp. 87-101. | + | [1] Almeida, Durao and Heitor, 1993, Experimental thermal and fluid science, Vol. 7, pp. 87-101. |
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| + | [2] [http://cfd.mace.manchester.ac.uk/ercoftac/database/cases/case81/Case_ref/IfH_paper.ps Mellen, Frohlich, Rodi], 2000, Large Eddy Simulation of the flow over periodic hills, 16th IMACS World Congress , Lausanne. | ||
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| + | [3] [http://cfd.mace.manchester.ac.uk/ercoftac/database/cases/case81/Case_ref/TSFP2_09032001.ps 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. | ||
| − | [ | + | [4]Spalding, 1961, A single formula for the law of the wall, Jl. Appl. Mech., vol 28, pp. 455-457 |
| − | [ | + | [5] Manhart Peller and Brun, 2008, Near-wall scaling for turbulent boundary layers with adverse pressure gradient, Theor. Comput. Fluid Dyn., vol 22 , pp. 243-260. |
Back to [[Sig Turbulence]] | Back to [[Sig Turbulence]] | ||
Revision as of 09:47, 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 Hills : 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]]. 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 figure 1.
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
2.1 Flow configuration
2.1.1 Geometrical Parameters
- Hill's heigh :
- Streamwise distance :
- Normal wall heigh :
- Spanwise distance :
2.1.2 Boundary condition
- Streamwise condition : periodicity
- Spanwise condition : periodicity
- Normal to streamwise : two walls
2.2 Simulation details
We have make the geometry on Gambit Fig 2 and the mesh is composed by 
.
The aim of my study is testing a posteriori near-wall low. To compare we are running three case :
- With near-wall low
- With the Spalding Low [5]
- Wiht the Mahart et al. low [6]
3 Numerical results
4 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.
[4]Spalding, 1961, A single formula for the law of the wall, Jl. Appl. Mech., vol 28, pp. 455-457
[5] Manhart Peller and Brun, 2008, Near-wall scaling for turbulent boundary layers with adverse pressure gradient, Theor. Comput. Fluid Dyn., vol 22 , pp. 243-260.
Back to Sig Turbulence
