What advection and transient scheme should I use for a DES simulation?
You should typically choose a 'High Resolution' or 'Specified Blend Factor' scheme for the advection, and the 'Second Order Backward Euler' scheme for the transient discretisation.
With this the solver will use the following:
- a 'High Resolution' or 'Specified Blend Factor' scheme for the momentum equations in the RANS region, a 'Central Difference' scheme in the LES region.
- an upwind scheme for the turbulence equations everywhere
- a second order transient scheme on the momentum
- a first order transient on the turbulence model
For a DES run, CFX-Pre 5.7 was wrongly suggesting that you should set the advection scheme to 'Central Difference'. This has been corrected from the CFX-5.7 Service Pack version.
Some more useful information on the DES model can be obtained from the validation report on the CFX Community pages (section CFX-5, validation): Development and application of a zonal DES turbulence model for CFX-5.