Difference between revisions of "Sig Turbulence / Flow over Periodic Hills"
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==== Boundary condition ==== | ==== Boundary condition ==== | ||
| − | Streamwise condition : periodicity | + | * Streamwise condition : periodicity |
| − | Spanwise condition : periodicity | + | * Spanwise condition : periodicity |
| − | Normal to streamwise : two walls | + | * Normal to streamwise : two walls |
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=== Simulation details === | === Simulation details === | ||
Revision as of 09:30, 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]]
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
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 :
2.1.1 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 
.
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.
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