Towards an Improved Subgrid-Scale Model for Thermally Driven Flows

  • Riccardo Togni
  • Andrea Cimarelli
  • Elisabetta De AngelisEmail author
Conference paper
Part of the Springer Proceedings in Physics book series (SPPHY, volume 196)


The effect of the filtering on the resolved and subgrid dynamics of turbulent Rayleigh–Bénard convection (RBC) is studied a priori using a Direct Numerical Simulation dataset. To this end, the velocity and temperature fields, split into resolved and subgrid components by a spectral cutoff filter, are analyzed with the filtered turbulent kinetic energy and temperature variance budgets. At small filter lengths, the resolved processes correspond to the exact ones except for the decreases of the dissipations which, in turn, are balanced by the sink actions of the subgrid scales. At large filters lengths, the resolved dynamics depletes close to the walls and the effect of the subgrid scales drifts from purely-dissipative to a more complex behaviour. This study highlights the possibility that eddy-viscosity and diffusivity models, commonly employed in large-eddy simulation of RBC, does not work well for large filter widths and that alternative closures should be considered.


  1. 1.
    U. Piomelli, Large-eddy simulation: achievements and challenges. Prog. Aerosp. Sci. 34(4), 335–412 (1999)CrossRefGoogle Scholar
  2. 2.
    F. Chillà, J. Schumacher, New perspectives in turbulent Rayleigh–Bénard convection. Eur. Phys. J. E 35(7), 1–25 (2012)CrossRefGoogle Scholar
  3. 3.
    C. Härtel, L. Kleiser, F. Unger, R. Friedrich, Subgrid-scale energy transfer in the near-wall region of turbulent flows. Phys. Fluids 6(9), 3130–3130 (1994–present)Google Scholar
  4. 4.
    R. Togni, A. Cimarelli, E. De Angelis, Physical and scale-by-scale analysis of Rayleigh–Bénard convection. J. Fluid Mech. 782, 380–404 (2015)MathSciNetCrossRefGoogle Scholar
  5. 5.
    Q. Zhou, C. Sun, K.Q. Xia, Morphological evolution of thermal plumes in turbulent Rayleigh–Bènard convection. Phys. Rev. Lett. 98(7), 074501 (2007)CrossRefGoogle Scholar
  6. 6.
    S. Grossmann, D. Lohse, Scaling in thermal convection: a unifying theory. J. Fluid Mech. 407, 27–56 (2000)MathSciNetCrossRefzbMATHGoogle Scholar
  7. 7.
    W.H. Cabot, Large Eddy simulations of time-dependent and buoyancy-driven channel flows. Annual research briefs (NASA Ames/Stanford University, Stanford, 1993)Google Scholar

Copyright information

© Springer International Publishing AG 2017

Authors and Affiliations

  • Riccardo Togni
    • 1
  • Andrea Cimarelli
    • 2
  • Elisabetta De Angelis
    • 3
    Email author
  1. 1.DIN, Università di BolognaForlìItaly
  2. 2.DISMI, Università degli Studi di Modena e Reggio EmiliaReggio EmiliaItaly
  3. 3.School of EngineeringCardiff UniversityCardiffUK

Personalised recommendations