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Hybrid LES-RANS Method Based on an Explicit Algebraic Reynolds Stress Model

  • Michael Breuer
  • Benoît Jaffrézic
  • Antonio Delgado
Part of the Notes on Numerical Fluid Mechanics and Multidisciplinary Design book series (NNFM, volume 97)

Abstract

Although LES is a highly promising simulation technique, it still suffers from extremely large resources required for the resolution of the near-wall region, especially for high-Re flows. That is the main motivation for setting up hybrid LES-RANS methods. Whereas RANS suits reasonably well to attached boundary layers, requiring much less CPU-time and memory than LES, the latter is recommended for complex large-scale flow phenomena, which RANS often fails to predict correctly. Both characteristics are combined in hybrid LES-RANS methods to obtain an optimal solution at lower cost. Meanwhile a variety of different hybrid concepts were proposed including DES. In the present study a non-zonal approach based on two different but unique models is preferred. The predefinition of RANS and LES regions is avoided and a gradual transition between both methods takes place which weakens the problem of setting up an appropriate coupling strategy. The new hybrid LES-RANS approach relies on a one-equation model for the turbulent kinetic energy in both modes. At this phase the model is of linear type. In addition to this linear eddy-viscosity model (LEVM), an explicit algebraic Reynolds stress model (EARSM) is applied in the RANS mode in order to account for the Reynolds stress anisotropy. This insertion leads to a non-linear model. The linear version is used for comparison in order to emphasize the advantages of the non-linear formulation. Both model variants have been tested on the basis of the standard plane channel flow and the flow over a periodic arrangement of hills.

Keywords

Reynolds Stress Separate Shear Layer RANS Region Attached Boundary Layer Reynolds Stress Anisotropy 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. Breuer, M.: Large–Eddy Simulation of the Sub–Critical Flow Past a Circular Cylinder: Numerical and Modeling Aspects. Int. J. for Num. Methods in Fluids 28, 1281–1302 (1998)zbMATHCrossRefGoogle Scholar
  2. Breuer, M., et al.: A Comparative Study of the Turbulent Flow Over a Periodic Arrangement of Smoothly Contoured Hills, Sixth Int. In: ERCOFTAC Workshop on DNS and LES: DLES-6, Poitiers, France, September 12–14, 2005. ERCOFTAC Series, vol. 10, pp. 635–642. Springer, Heidelberg (2006)Google Scholar
  3. Breuer, M., Jaffrézic, B., Arora, K.: Hybrid LES-RANS Technique Based on a One-Equation Near-Wall Model. J. Theoretical and Computational Fluid Dynamics (in press, 2007)Google Scholar
  4. Breuer, M.: New Reference Data for the Hill Flow Test Case, personal communication (2005), http://www.hy.bv.tum.de/DFG-CNRS/
  5. Fröhlich, J., et al.: Highly Resolved Large–Eddy Simulation of Separated Flow in a Channel with Streamwise Periodic Constrictions. J. Fluid Mech. 526, 19–66 (2005)zbMATHCrossRefMathSciNetGoogle Scholar
  6. Jaffrézic, B., et al.: Towards LES-RANS-Coupling for Complex Flows with Separation. In: ESAIM Proceedings, CEMRACS 2005, Computational Aeroacoustics and CFD in Turbulent Flows, Marseille, France, July 18– August 26, 2005, vol. 16, pp. 89–113 (2007)Google Scholar
  7. Moser, R.D., Kim, J., Mansour, N.N.: DNS of Turbulent Channel Flow up to Reτ=590. Phys. Fluids 28, 1281–1302 (1999)Google Scholar
  8. Rodi, W., Mansour, N.N., Michelassi, V.: One-Equation Near-Wall Turbulence Modeling with the Aid of Direct Simulation Data. J. Fluids Engineering 115, 196–205 (1993)CrossRefGoogle Scholar
  9. Schumann, U.: Subgrid–Scale Model for Finite–Difference Simulations of Turbulent Flows in Plane Channels and Annuli. J. Computational Physics 18, 376–404 (1975)zbMATHCrossRefMathSciNetGoogle Scholar
  10. Wallin, S., Johansson, A.V.: An Explicit Algebraic Reynolds Stress Model for Incompressible and Compressible Turbulent Flows. J. Fluid Mech. 403, 89–132 (2000)zbMATHCrossRefMathSciNetGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2008

Authors and Affiliations

  • Michael Breuer
    • 1
  • Benoît Jaffrézic
    • 1
  • Antonio Delgado
    • 1
  1. 1.LSTMUniversity of Erlangen-NürnbergGermany

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