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Integration of grey area turbulence models from Upstream CFD

Andrew Heather requested to merge feature-grey-area-turbulence into develop


  • Refactoring of Spalart-Allmaras (SA) models​
    • New class hierarchy to reduce code duplication​
    • Trip term (ft2) now on a user switch​
      • Was previously active, now deactivated by default
  • Enhancements to DES models to include grey area model effects in collaboration with @MarianFuchs, Upstream CFD GmbH
    • sigma extension for SA and k-omega DES, DDES models​
    • New LES delta functions​
      • DeltaOmegaTilde​
      • SLADelta​
    • New sigma LES model​
  • Extended turbulenceFields function object​
    • Added writing of DES shielding function (fd) and LES region indicator fields​
  • Added warnings for DES model usage; DDES forms should be employed instead

Details of new models (If applicable)

Grey area turbulence

The new sigma treatment is available for the models:

  • SpalartAllmarasDES, SpalartAllmarasDDES, SpalartAllmarasIDDES

and activated via the useSigma switch, e.g.

simulationType LES;

    LESModel        SpalartAllmarasDDES;
        useSigma        true;                    // <-- new entry

    //delta           SLADelta; // DeltaOmegaTilde;
    delta           DeltaOmegaTilde;


Test case: wallMountedHump.tgz provided by @MarianFuchs


  • Mockett, C. et al. (2015). Two Non-zonal Approaches to Accelerate RANS to LES Transition of Free Shear Layers in DES. In: Girimaji, S., Haase, W., Peng, SH., Schwamborn, D. (eds) Progress in Hybrid RANS-LES Modelling. Notes on Numerical Fluid Mechanics and Multidisciplinary Design, vol 130. Springer, Cham.
  • Fuchs, M. et al. (2016). Further Assessment of the Grey-Area Enhanced σ-DES Approach for Complex Flows. ERCOFTAC Bulletin 108
  • Fuchs, M. et al. (2015). Assessment of novel DES approach with enhanced SGS modelling for prediction of separated flow over a delta wing. AIAA 2015-3433.

Extended turbulenceFields function object

The turbulenceFields function object now included writing for:

  • fd : DES shielding function
  • LESRegion : LES indicator field

An example usage has been added to the $FOAM_TUTORIALS/incompressible/pimpleFoam/LES/vortexShed case:

       type            turbulenceFields;
       libs            (fieldFunctionObjects);
       writeControl    writeTime;
       fields          (fd LESRegion);



  • Possible regressions in SA models following code refactoring

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