Hi, everyone I wonder can a DNS code directly be used to perform ILES without any revision. The difference between DNS and ILES is the requirement of mesh resolution from the view of implemention, right? Moreover, does the ILES have the procedure of filtering? What properties are needed for the num…

Not all DNS schemes are suitable for ILES; it depends on their dispersion and dissipation relationship. Namely, that unresolved scales need to be subject to a reasonable degree of dissipation. The FR schemes used by PyFR are suitable without any modification. Regards, Freddie.

Further to this, there is no filtering in ILES as the filter is implicit from the numerical scheme. If you were to set a filter explicitly then you are on the road to LES. Consider “Turbulent Flows” by Pope, chapter 13. What properties are needed from a numerical scheme to be suitable for ILES is a…

Thank you for your kind reply! As you mentioned, the filter is controlled by the grid and mesh can be very important. Is it meaningful to do grid independence study since the grid has a significant impact on the results in ILES？

Yes. The hypothesis behind LES is that one only needs to resolve the large scale structures to obtain measurements which are suitable for typical engineering purposes. However, what counts as a ‘large’ structure is not clear cut and the importance of resolving a specific structure depends very muc…

Some questions about implicit LES

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WillT Split this topic 8 June 2023 19:52 6

A post was split to a new topic: Polynomial grid convergence studies

Topic		Replies	Views
Polynomial grid convergence studies Cases	2	212	8 June 2023
ILES model problem? General	2	375	9 June 2022
Subgrid wall model General	4	187	31 December 2023
Turbulent Channel Flow ini file - JFM 2019 General	3	573	25 August 2021
Mesh resolution, order, and curved boundaries General	12	1754	17 August 2021

Some questions about implicit LES

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