Evaluation of high-pass filtered eddy-viscosity models for large-eddy simulation of turbulent flows

Large-eddy simulations (LES) of incompressible homogeneous isotropic turbulence and turbulent channel flow are performed at moderate Reynolds numbers using high-pass filtered (HPF) eddy-viscosity models. This family of models computes the subgrid-scale (SGS) terms from a high-pass filtered velocity field using classical closure relations, e.g. the Smagorinsky or the structure–function model closure. Unlike the classical fixed-coefficient eddy-viscosity models, the HPF models are able to accurately describe the viscous sublayer of near-wall turbulence. Moreover, it has been shown recently that the HPF models are also capable of predicting transitional flows.

Detailed results of energy and dissipation spectra are given for forced isotropic turbulence at microscale Reynolds number up to Re _λ≈5500. For turbulent channel flow at friction Reynolds number Re _τ≈590, results are presented for first- and second-order statistics as well as for the energy budget including the SGS terms. The overall performance of the HPF eddy-viscosity models is very good for both flow cases using a constant model coefficient. An empirical adaptation of the model coefficient to the cutoff wavenumber of the chosen high-pass filter is given. In contrast to classical eddy-viscosity models, the HPF models allow the prediction of backscatter effects, which are important for wall-bounded flows close to the walls.

Notes

^†DNS data interpolated onto LES grid.

^‡DNS with 384²×257 grid points.