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DES formulated with ILES rather than classical LES

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Old   August 7, 2013, 06:28
Default DES formulated with ILES rather than classical LES
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siw
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Hi,

As we know Detached Eddy Simulation is a hybrid method switching between RANS (e.g. with the Spalart-Allmaras model) and classical LES (e.g. with the Smagorinsky SGS model) via a length scale term and grid cell size.

Since Implicit LES does not have a SGS model, but instead uses the numercial scheme for dissipation, is it possible to formulate DES with ILES instead of classical LES? I don't think it can becuase of the lack of a SGS model but would like to know what others think.

Thanks
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Old   August 7, 2013, 07:15
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Quote:
Originally Posted by siw View Post
Hi,

As we know Detached Eddy Simulation is a hybrid method switching between RANS (e.g. with the Spalart-Allmaras model) and classical LES (e.g. with the Smagorinsky SGS model) via a length scale term and grid cell size.

Since Implicit LES does not have a SGS model, but instead uses the numercial scheme for dissipation, is it possible to formulate DES with ILES instead of classical LES? I don't think it can becuase of the lack of a SGS model but would like to know what others think.

Thanks
In principle, if you recognize that the numerical scheme produces a local truncation error able to mimic the eddy viscosity model LES and ILES solutions can produce equivalent statistics. This requires special numerical schemes. I such cases DES would result feasible.
However, in general ILES can not mimic the behaviour of more sophysticated SGS model ...

you can find useful the reading of

http://www.academia.edu/836591/Impli...ddy_Simulation

http://books.google.it/books/about/I...sC&redir_esc=y
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Old   August 7, 2013, 11:28
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Check this:

http://dx.doi.org/10.1016/j.ijheatfluidflow.2003.11.021

and the references cited therein. However, the basic idea should be to let the DES model tend toward a null model in the LES zone (instead of a classic Smagorinsky model).
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