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TWiki> CfdTm Web>TestCase023>TestCase023Res000 (2011-09-02, DavidMonfort)

TWiki> CfdTm Web>TestCase023>TestCase023Res000 (2011-09-02, DavidMonfort)

*Version:* 2.0-beta2

*Authors:* K. Osman

ID | Turbulence model | Options | Code version | Other |
---|---|---|---|---|

KE1 | k-epsilon | 1.3 | ||

KE2 | k-epsilon | 2.0 | ||

KE3 | k-epsilon | `IDEUCH=0` |
1.3 | |

KE4 | k-epsilon | `IDEUCH=0` |
2.0 | |

KE5 | k-epsilon | 2.0 | CCRT (Platine) in parallel | |

KE6 | k-epsilon | flux reconstruction | 2.0 | |

KEPL1 | k-epsilon with linear production | 1.3 | ||

KEPL2 | k-epsilon with linear production | 2.0 | ||

KEPL3 | k-epsilon with linear production | `IDEUCH=0` |
1.3 | |

KEPL4 | k-epsilon with linear production | `IDEUCH=0` |
2.0 | |

KEPL5 | k-epsilon with linear production | flux reconstruction | 2.0 | |

SSG1 | Rij-SSG | 1.3 | ||

SSG2 | Rij-SSG | 2.0 | ||

SSG3 | Rij-SSG | `IDEUCH=0` |
1.3 | |

SSG4 | Rij-SSG | `IDEUCH=0` |
2.0 | |

SSG5 | Rij-SSG | `ICLSYR=1` |
1.3 | |

SSG6 | Rij-SSG | `ICLSYR=1` |
2.0 | |

SSG7 | Rij-SSG | `ICLSYR=1` , `IDEUCH=0` |
1.3 | |

SSG8 | Rij-SSG | `ICLSYR=1` , `IDEUCH=0` |
2.0 |

*Nota bene:* If not specified the calculations are run on a Calibre workstation (Calibre 5 for the calculations run with version 2.0). Both RIJ-SSG and k-epsilon models use by default `IDEUCH=1`

Figures (1), (2) and (3) compares the different models %$k-\varepsilon$% with and without linear production and %$R_{ij}-\varepsilon$% model with or without the partial implicitation of symmetry conditions. Figure (1) shows the Nusselt number predictions, with results using the versions 1.3 and 2.0. Figures (2) and (3) present the velocity and turbulent kinetic energy profile for the vesion 2.0. The new version of the code gives the same Nusselt number prediction as the previous version. The patch p03 regarding the algebraic multigrid for the pressure equation was used on some cases, with no influence on the results.

Activating the partial implicitation of symmetry condition enables to get results closer to the experimental measurements. This can be seen on the Nusselt plot figure (1) as well as the velocity and turbulence profiles, figures (2) and (3).

The linear production %$k-\varepsilon$% enables to reduce the problem of turbulence over-prediction observed with the original model towards the stagnation point.

Same results are obtained using the %$k-\varepsilon$% model whether it is used on the Calibre workstation or the Platine CCRT machine in parallel.

The use of the flux reconstruction in the equations of %$k$% and %$\varepsilon$% for the models %$k-\varepsilon$% with and without linear production has little influence. This was to be expected since the mesh is quasi orthogonal (about 100 000 boundary faces with a non-orthogonality angle below 7°, and less than 1000 above).

`IDEUCH=0`

Using a one velocity wall function ( `IDEUCH=0`

) yields a behaviour different from the the experimentally observed one, towards the centre of the plate. Activating `IDEUCH=1`

(two-velocity wall function) leads to a better matching with the measures. With a one velocity wall function the number of cells falling into the viscous sublayer is much more important, which may explain the observed difference of results.

Topic revision: r28 - 2011-09-02 - 09:44:08 - DavidMonfort

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