Vorticity, backscatter and counter-gradient transport predictions using two-level simulation of turbulent flows. Issue 4 (3rd April 2018)

• Record Type: Journal Article
• Authors: Ranjan, R.; Menon, S.
• Is Part Of: Journal of turbulence. Volume 19:Issue 4(2018)
• Page Start: 334
• Page End: 364
• Publication Date: 2018-04-03
• Subjects: Two-level simulation -- large eddy simulation -- vorticity -- turbulent transport -- backscatter; Turbulence -- Periodicals; Turbulence -- Périodiques; 532.0527
• DOI: 10.1080/14685248.2018.1438616
• Languages: English
• ISSNs: 1468-5248

Abstract

ABSTRACT: The two-level simulation (TLS) method evolves both the large-and the small-scale fields in a two-scale approach and has shown good predictive capabilities in both isotropic and wall-bounded high Reynolds number ( Re ) turbulent flows in the past. Sensitivity and ability of this modelling approach to predict fundamental features (such as backscatter, counter-gradient turbulent transport, small-scale vorticity, etc.) seen in high Re turbulent flows is assessed here by using two direct numerical simulation (DNS) datasets corresponding to a forced isotropic turbulence at Taylor's microscale-based Reynolds number Re λ ≈ 433 and a fully developed turbulent flow in a periodic channel at friction Reynolds number Re τ ≈ 1000. It is shown that TLS captures the dynamics of local co-/counter-gradient transport and backscatter at the requisite scales of interest. These observations are further confirmed through a posteriori investigation of the flow in a periodic channel at Re τ = 2000. The results reveal that the TLS method can capture both the large- and the small-scale flow physics in a consistent manner, and at a reduced overall cost when compared to the estimated DNS or wall-resolved LES cost.