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Useful LES tools in Fluent - Part 4

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Useful LES tools in Fluent - Part 4

Posted March 7, 2014 at 03:59 by sbaffini

This is a routine to perform a remap of fields from an interior surface to an inlet surface during the computation. In practice this can be used to produce an LES inflow belonging to the class of the so called "precursor methods". Still, this is actually done in parallel with the main computation and not in advance.

The attached pdf file contains an explanatory image of the method while the .c routine should be sufficiently commented to be readily usable by anyone who actually knows what i'm talking about. If you don't, then you don't need it.

The routine only works in parallel (a serial version is available on request but its use is pointless in LES) and has been tested on straight circular and square ducts, both with structured and unstructured grids.

When compared with the default methods in Fluent (Vortex Method and Spectral Synthesizer) on the same number of cells, it is found to be around the 18% faster on average (different parallel partitions, load balances and hardware architectures). When the parallel partitioning is optimized the saving is higher.

A preliminary testing of the procedure has been presented here:


While additional details will be present in my forthcoming Ph.D. thesis, which i will share as soon as i will defend it.

The auxiliary flow is driven by a fixed source term (which nonetheless can be easily modified). An alternative version based on a PID controller to fix the mass flow rate and/or an additional integral parameter (say, the swirl number) is also available on request. However, this PID version has not been toroughly tested and some additional work might be needed.
Attached Files
File Type: c remap_par.c (14.4 KB, 144 views)
File Type: pdf remap.pdf (24.2 KB, 155 views)
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  1. Old Comment

    Thank you for this work - it seems very interesting, and it could help me with my simulations. When I download the text file, however, the entire code appears as one big chunck of text. Could you maybe reupload the text file, where the code can be better understood or can you maybe just post the code somewhere on this website?

    Thanks in advance for your help!
    Posted November 8, 2015 at 13:38 by TimotheusFlavii TimotheusFlavii is offline
  2. Old Comment
    sbaffini's Avatar
    You have 3 options:

    1) Open it with wordpad
    2) Open it under Linux
    3) Do "unix2dos remap_par.c" in a linux shell, then use it under windows
    Posted November 8, 2015 at 14:09 by sbaffini sbaffini is offline

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