An analysis of subgrid-resolved scale interactions with use of results from direct numerical simulations

Gong, H.; Chen, S.; He, Guowei

doi:10.1007/bf02485875

Cited by 4 publications

(2 citation statements)

References 9 publications

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“…Inspired by Kraichnan (1967); Gong et al (1999); Vallis (2017); Zhou (2021), here we will discuss three categories of triad interactions in spectral space under the scale separation of clear and unclear spectral truncation and reveal its relationship with Leonard's decomposition.…”

Section: Appendix B: Leonard's Decomposition and Triad Interactionmentioning

confidence: 99%

A Multifaceted Isoneutral Eddy Transport Diagnostic Framework and Its Application in the Southern Ocean

Xie

Liu

Lin

2023

J Adv Model Earth Syst

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We propose an isoneutral eddy transport diagnostic framework and apply it in the Southern Ocean to analyze eddy potential vorticity (PV) transport dynamics. We leverage a thickness‐weighted spatiotemporal scale separation to define the generalized eddy flux. A local sampling method is employed and validated to estimate the transport tensor. We introduce Leonard's decomposition in Large Eddy Simulations (LES) to split the process into the Reynolds and non‐Reynolds parts. We also use the stationary‐transient decomposition. The non‐Reynolds term and the stationary effect contribute significantly to the transport properties. The Reynolds and transient parts have distinctions, that show oceanic mesoscale dynamics are not synergistic in time and spatial scales. We investigate the spatial scale dependence of each part and find that the transient and stationary components of the Reynolds (non‐Reynolds) term have consistent (dissimilar) scale dependence. The scale dependence of the generalized eddy flux and the transport eigenvalues is controlled by the non‐Reynolds term. We further investigate the eigenvalues in terms of the potential enstrophy and anisotropy. The potential enstrophy in the Southern Ocean holistically has a forward cascade on the researched scales. The Reynolds and transient effects efficiently promote the forward enstrophy cascade. The non‐Reynolds and stationary effects stimulate drastically anisotropic eddy transport. The PV gradient barrier mechanism dominates the drastic anisotropic case. When the anisotropy is weak, a special anisotropic case with a locally balanced potential enstrophy budget overwhelms the case of real isotropy. We also introduce several LES concepts, hoping to enlighten any potential ocean modeling and parameterization.

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Section: Appendix B: Leonard's Decomposition and Triad Interactionmentioning

confidence: 99%

A Multifaceted Isoneutral Eddy Transport Diagnostic Framework and Its Application in the Southern Ocean

Xie

Liu

Lin

2023

J Adv Model Earth Syst

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show abstract

“…Inspired by Kraichnan (1967); Gong et al (1999); Vallis (2017); Zhou (2021), here we will discuss three categories of triad interaction in spectral space under scale separation of clear and unclear spectral truncation and reveal its relationship with Leonard's decomposition.…”

Section: Appendix Amentioning

confidence: 99%

A multifaceted isoneutral eddy transport diagnostic framework and its application in the Southern Ocean

Xie

Liu

Lin

2022

Preprint

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We propose a multifaceted isoneutral eddy transport diagnostic framework that combines the stationary-transient and Leonard's decomposition in large eddy simulation (LES). We diagnose the subfilter flux, the isotropic transport coefficient, and the anisotropic transport tensor or eigenvalues in the Southern Ocean (SO). The anisotropic tensor greatly reduces the reconstruction error of the subfilter flux because of its ability to distinguish the directionality of dynamic information, especially the topographic effect. A thorough analysis of the anisotropic tensor or transport eigenvalues reveals that the sign combination of the transport eigenvalues of the symmetric tensor links to the evolution of domainintegral large-scale PV enstrophy and the combination of different signs is most often, meaning the dominance of filamentation process in the SO. In the region with intense anisotropy, the dominant eigenvector tends to be perpendicular to the large-scale PV gradient, indicating an important role of the PV barrier mechanism in the SO transport process. The two distinct decompositions leveraged in our framework generate intriguing and profound results. Under the stationary-transient decomposition, we find a significant stationary contribution and the duality of the topographic effect which can not only anchors stationary structures but also organizes transient motions. Leonard's decomposition, allows us to investigate the collective effects of the standing wave train, cross-scale interaction, and subfilter eddy-eddy interaction on the filtered space-time scale. We emphasize the complete subgrid flux, not the mere Reynolds term, and the LES framework needs to be considered in the subgrid parameterization of the coarse resolution ocean model.

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Large eddy simulation of complex turbulent flows: Physical aspects and research trends

李家春

2001

Acta Mech Sinica

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In the current paper, we have primarily addressed one powerful simulation tool developed during the last decades Large Eddy Simulation (LES), which is most suitable for unsteady three-dimensional complex turbulent flows in industry and natural environment. The main point in LES is that the large-scale motion is resolved while the small-scale motion is modeled or, in geophysical terminology, parameterized. With a view to devising a subgrid-scale(SGS) model of high quality, we have highlighted analyzing physical aspects in scale interaction and energy transfer such as dissipation, backscatter, local and non-local interaction, anisotropy and resolution requirement. They are the factors responsible for where the advantages and disadvantages in existing SGS models come from. A case study on LES of turbulence in vegetative canopy is presented to illustrate that LES model is more based on physical arguments. Then, varieties of challenging complex turbulent flows in both industry and geophysical fields in the near future are presented. In conclusion, we may say with confidence that new century shall see the flourish in the research of turbulence with the aid of LES combined with other approaches.

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An analysis of subgrid-resolved scale interactions with use of results from direct numerical simulations

Cited by 4 publications

References 9 publications

A Multifaceted Isoneutral Eddy Transport Diagnostic Framework and Its Application in the Southern Ocean

A Multifaceted Isoneutral Eddy Transport Diagnostic Framework and Its Application in the Southern Ocean

A multifaceted isoneutral eddy transport diagnostic framework and its application in the Southern Ocean

Large eddy simulation of complex turbulent flows: Physical aspects and research trends

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