Nonlinear Subgrid-Scale Models for Large-Eddy Simulation of Rotating Turbulent Flows

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.

Toward neural-network-based large eddy simulation: application to turbulent channel flow

“…is the kernel of the filter (Bedford & Yeo 1993). On the other hand, a general class of SGS model based on the local velocity gradient (Lund & Novikov 1992;Silvis et al 2019) can be expressed as…”

Effects of sampling frequency on the proper orthogonal decomposition based reconstruction of a wind turbine wake

“…LES is a high-fidelity and effective CFD method that is broad used in the research of turbulence analysis [25][26][27] and wind farm computations [28][29][30]. In this study, in-house LES code LESGO [31] is used to compute the 3D flow field around a wind turbine in a neutral atmospheric boundary layer.…”

A-priori evaluation of data-driven models for large-eddy simulations in natural convection

“…The GEP model shows high similarity with the target, whereas the wall-adapting local eddy-viscosity (WALE) model [5], which is a popular linear model in industry, heavily over-estimates the shear stress. Additionally, a recent non-linear model proposed by Silvis [9] is also used for comparison. Even though the magnitude predicted by the non-linear model is at the same level as the target, the distribution of SGS stress is different.…”

“…Even though the magnitude predicted by the non-linear model is at the same level as the target, the distribution of SGS stress is different. There are more fine structures compared to the Gaussian-filtered DNS and the reason for this is that the non-linear model proposed by Silvis [9] only contains two terms (T 1 and T 2) and these two terms alone cannot produce the correct stress field. Figure 9 quantitatively indicates the similarity between the targets and GEP models by using the Pearson correlation.…”