Improvement of double-buffer problem in LES-RANS interface region by introducing an anisotropy-resolving subgrid-scale model

• 安倍, 賢一

  九州大学大学院工学研究院航空宇宙工学部門

抄録

The "double-buffer problem" has been regarded as a crucial concern for the strategy behind the hybrid large eddy simulation (LES)/Reynolds-veraged Navier-Stokes (RANS) model (or HLR model, for short). Such models are likely to show unphysical mean-velocity distributions in the LES-RANS interface region, where "super-streak structures" also appear that look like low-speed streaks generated in the near-wall region of wall turbulence. To overcome this difficulty, the stochastic backscatter model, in which the vortex structures in the interface region are divided into smaller scales, holds promise due to the effect of random source term imposed in the momentum equation. Although this method is effective, several parameters must be prescribed and their specification process is arbitrary and ambiguous. An alternative advanced HLR model has been proposed, in which an anisotropy-resolving subgrid scale (SGS) model was adopted in the LES region as well as a one-equation non-linear eddy-viscosity model in the RANS region. Previous investigations indicated that this HLR model did not exhibit or, at least, largely reduced the "double-buffer problem" in the mean-velocity distribution, with no special treatment being applied. The main purpose of the present study is to reveal why this HLR model improves the predictive performance in the LES-RANS interface region. Specifically, we focus on the role of the extra anisotropic term introduced in the SGS model, finding that it plays an important role in enhancing vortex structures in the interface region, leading to a considerable improvement in model performance.

収録刊行物

• Theoretical and Computational Fluid Dynamics

  Theoretical and Computational Fluid Dynamics 32 (3), 263-283, 2018-02-07

  Springer nature

キーワード

• Turbulence
• Large Eddy Simulation
• Anisotropy-Resolving SGS Model
• Hybrid LES/RANS Model
• Interface Region

詳細情報

• CRID: 1050017057727329024
• NII論文ID: 120006952139
• NII書誌ID: AA11631687
• DOI: 10.1007/s00162-018-0453-5
• ISSN: 14322250
• ISSN: 09354964
• HANDLE: 2324/4150684
• Web Site: http://link.springer.com/article/10.1007/s00162-018-0453-5/fulltext.html
• Web Site: http://link.springer.com/content/pdf/10.1007/s00162-018-0453-5.pdf
• 本文言語コード: en
• 資料種別: journal article
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