A comparative study on the large-scale-resolving capability of wall-modeled large-eddy simulation

Abstract

Wall-modeled large-eddy simulation (WMLES) could be a useful predictive tool in high-Reynolds-number wall-bounded turbulent flows that are ubiquitous in nature and engineering, but its capability to resolve large-scale energy-containing outer motions has yet to be assessed comprehensively. In this study, moderately high-Reynolds-number turbulent channel flows up to Reτ ≈ 5200 are simulated by WMLES with various subgrid-scale (SGS) models and wall models in comparison with direct-numerical simulation data. The main objective is to assess the predictive capability of WMLES in the context of the turbulence kinetic energy spectrum in the outer region. Four classical eddy-viscosity-type SGS models are compared, i.e., the Smagorinsky model, the Lagrangian dynamic model, the Lagrangian scale-dependent (LASD) model, and the Vreman model. It is shown that the performance of the LASD model is superior to others in predicting one-point statistics as well as kinetic energy spectra. Three types of wall models are involved, i.e., the equilibrium wall model, the slip-wall model, and the integral wall model. We find that the wall model does not significantly affect prediction of turbulence fluctuations in the outer region. Although near-wall turbulent motions are not fully resolved in WMLES, we clearly show that the spectral characteristics of large-scale energy-containing turbulent motions in the outer region can reasonably be predicted with appropriate models. We also provide a preliminary discussion on the effects of domain setup and grid resolution. The difference in the spectral energy distribution between full- and half-channel flows is also reported.