A nonlinear subgrid-scale model for large-eddy simulations of rotating turbulent flows

TL;DR

This paper introduces a new nonlinear subgrid-scale model for large-eddy simulations of rotating turbulent flows, effectively capturing energy dissipation and backscatter, and improving predictions across various flow scenarios without needing dynamic adjustments.

Contribution

The paper proposes a novel nonlinear SGS model with physically consistent coefficients, validated through DNS and LES, outperforming existing models in rotating turbulent flow simulations.

Findings

The nonlinear term improves Reynolds stress anisotropy predictions.

The model accurately predicts rotating decaying turbulence.

It outperforms traditional models in spanwise-rotating channel flow.

Abstract

Rotating turbulent flows form a challenging test case for large-eddy simulation (LES). We, therefore, propose and validate a new subgrid-scale (SGS) model for such flows. The proposed SGS model consists of a dissipative eddy viscosity term as well as a nondissipative term that is nonlinear in the rate-of-strain and rate-of-rotation tensors. The two corresponding model coefficients are a function of the vortex stretching magnitude. Therefore, the model is consistent with many physical and mathematical properties of the Navier-Stokes equations and turbulent stresses, and is easy to implement. We determine the two model constants using a nondynamic procedure that takes into account the interaction between the model terms. Using detailed direct numerical simulations (DNSs) and LESs of rotating decaying turbulence and spanwise-rotating plane-channel flow, we reveal that the two model terms respectively account for dissipation and backscatter of energy, and that the nonlinear term improves predictions of the Reynolds stress anisotropy near solid walls. We also show that the new SGS model provides good predictions of rotating decaying turbulence and leads to outstanding predictions of spanwise-rotating plane-channel flow over a large range of rotation rates for both fine and coarse grid resolutions. Moreover, the new nonlinear model performs as well as the dynamic Smagorinsky and scaled anisotropic minimum-dissipation models in LESs of rotating decaying turbulence and outperforms these models in LESs of spanwise-rotating plane-channel flow, without requiring (dynamic) adaptation or near-wall damping of the model constants.