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-   -   Guidance for initializing a DES (http://www.cfd-online.com/Forums/cfx/114285-guidance-initializing-des.html)

siw March 8, 2013 07:37

Guidance for initializing a DES
 
Hi,

I'm about to start a simulation using Detached Eddy Simulation (in CFX it can only use the SST model for the RANS part). This is just to see how it all works rather than to get data for a job. I have not been able to find these answers anywhere, in particular the ANSYS Scale-Resolving Simulation Best Practice Guide by Menter.

However, I have a couple of questions about the initialization for a DES run:

1. Should a RANS (with SST) be conducted first to initialse the flowfield? I appreciate that in DES certain areas of the flowfield will be solved with LES so RANS data in those areas will not directly compatible but it should help in the near-wall regions. In the past I always initialize a URANS simulation with a RANS simulation; using the same mesh and turbulence model, to improve convergence.

2. If a pre-cursor RANS simulation is recommended should the RANS simulation use the DES mesh? Or can a coarser mesh be used for the RANS simulation by not including the resolution required for the LES regions of the DES.

Thanks.


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