A Priori Assessment of Subgrid‑Scale Models and Numerical Error in Forced Convective Flow at High Prandtl Numbers

Lorenzo Sufra, Helfried Steiner

Research output: Contribution to journalArticlepeer-review


An extensive a priori analysis has been carried out on data from Direct numerical simulation of fully developed heated turbulent pipe flow at high molecular Prandtl numbers Pr=10/20, testing three popular modelling candidates for subgrid-scale closure in Large-Eddy simulation (LES). Aside from assessing the models’ capabilities to describe quantitatively the unresolved turbulent fluxes, a special focus is also put on the role of the numerical error, which arises from the discretization of the filtered advective fluxes on a coarse LES grid. The present analysis extends here previous studies on subgrid-scale momentum transport in a isothermal mixing layer and channel flow carried out by Brandt (J Numer Methods Fluids 51: 635–657, 2006) and Vreman et al. (J Eng Math 29: 299–327, 1995), respectively, to the subgrid-scale transport of heat at high Prandtl numbers. The statistical dependence between the individual contributions (resolved, subgrid-scale, numerical discretization error) constituting the filtered advective flux divergence in the LES formulation is investigated as well, in terms of corresponding cross-correlations. The sensitivity of the tested sgs-models to a grid refinement is further examined performing also a posteriori LES, where the basically more sophisticated candidates turn out to be more demanding in terms of required grid resolution.
Original languageEnglish
Pages (from-to)377-392
Number of pages16
JournalFlow, Turbulence and Combustion
Issue number2
Early online dateJan 2020
Publication statusPublished - 1 Aug 2020


  • A priori LES
  • Grid sensitivity
  • Numerical error
  • Subgrid-scale closure

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Chemical Engineering(all)
  • Physical and Theoretical Chemistry

Fields of Expertise

  • Advanced Materials Science


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