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-   -   time stepping schemes for compressible DNS/LES (http://www.cfd-online.com/Forums/main/71794-time-stepping-schemes-compressible-dns-les.html)

shyamdsundar January 15, 2010 00:15

time stepping schemes for compressible DNS/LES
 
Hi,

I have a general doubt with compressible DNS/LES codes. Explicit schemes model both the length and time scales accurately while implicit schemes might not represent the time scales accurately due to large CFL. Besides, many implicit schemes are only second or 3rd order accurate. In case of DNS or LES where both length and time scales might be important, I am wondering which one should I choose. A lower CFL would naturally favor explicit schemes.

If one wants to develop an efficient unstructured higher order LES code based on DG, which one of the time stepping schemes is preferable?

Explicit (like RK-DG schemes)
Implicit ( Dual time stepping, etc. )
Explicit-Implicit (implicit near boundary, explicit at coarser grids)
Explicit-Explicit (variable time steps)


Thanks in advance for your reply.

Shyam


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