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Herry May 15, 2003 02:24

Turbulence model
 
HI everyone,

I just want to model a cubic around airflow model with turbulence model. However, i still do not know which is the best turbulence model for my model. Can you help me to choose which the suitable one. I hear it is good to use Ke-ep model. is that true?

regards, herry

Tim May 29, 2003 13:19

Re: Turbulence model
 
If you want to model the airflow around a cube, using the k-e model is a good start. There is no "best" model but the model you are looking for need be able to account for the distribution of length scales and velocity scales of turbulence properly. The airflow around a bluff body is characterised by flow separation and reattachment as well as vortex shedding. These phenomena are very challenging to turbulence modelling and one should not expect the turbulence "model" using eddy viscosity can predict these phenomena satisfactorily. Using Large Eddy Simulation (LES) has been proven superior in this type of flow simulation but it is more complicated because your boundary conditions must be time-dependent and you have to determine the time steps required for reliable statistics of turbulence. Also, you need the knowledge of the distribution of eddy sizes because your grids will determine how large the eddy is to be resolved in your simulation.

There are plenty of papers forcusing this issue and you are encourged to do a bit of literature survey.

Good luck.


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