Research on LES for Flows with Generation of Turbulence at Small Scales

小尺度湍流产生流的 LES 研究

• 批准号: 10650162
• 负责人: HORIUTI Kiyosi
• 金额: $ 2.05万
• 依托单位: Tokyo Institute of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10650162/
• 关键词: Vortex sheet and tube; Direct numerial simulation; Large-eddy simulation; Homogeneous-isotropic turbulence; Dissipation; Energy transfer; Subgrid-scale model; Smagorinsky model; Large-eddy simulation (LES); DNS; Subgrid-scaleエネルギー; Forward scat

The aim of the present study was to identify the structure which is most responsible for the transfer and dissipation of the turbulent energy, and conduct an assessment of the subgrid scale (SGS) models in large-eddy simulation (LES) on the accuracy for a prediction of energy transfer associated with these structures.We have developed a method to classify vortical structures into three categories, a flat sheet, a cylindrical sheet and a tube core. We generated direct numerical simulation (DNS) data of the homogeneous isotropic turbulence using 128ィイD13ィエD1 and 256ィイD13ィエD1 grid points for the cases with and without inputs of external energy at the large or small scales. It was shown using these databases that the proposed method yields an accurate classification of the data into three regions with the desired characteristics. By utilizing this method, we examined the contribution of these structures for the dissipation and cascade of turbulent energy in LES. It was shown that dissipati … More on and forward energy transfer primarily arises in the flat sheet region, whereas backward transfer primarily occurs in the compressed tube core region. In all of three regions, an intense generation of the azimuthal vorticity, placed perpendicular to the most stretched vorticity, was noticed.Then, we have conducted an assessment of the SGS models on its accuracy for prediction of the structures responsible for the transfer. The constant coefficient Smagorinsky model was an accurate model to represent the forward transfer. In the dynamic Smagorinsky model (DSM), the effect of the strain on the model was reduced, and an prediction accuracy for the structures responsible for energy transfer was significantly lowered.These SGS models were further assessed in actual LES. The Smagorinsky model yielded overestimate of forward transfer, and a poor prediction for an evolution of vortical structures. DSM yielded overestimate of contribution of the tube-core region, and a poor prediction of the dissipative structures. These drawbacks were circumvented in the SGS estimation model. Assessment of the results obtained in the present study at higher Reynolds numbers will be left to future work. Less

本研究的目的是确定对湍流能量的传递和耗散最有影响的结构，并对大涡模拟（LES）中的亚网格尺度（SGS）模型进行评估，以评估与这些结构相关的能量传递预测的准确性。我们开发了一种将涡流结构分为三类的方法，即平板、圆柱板和管芯。我们使用 128ィイD13ィエD1 和 256ィイD13ィエD1 网格点生成了在大尺度或小尺度有和没有外部能量输入的情况下均匀各向同性湍流的直接数值模拟 (DNS) 数据。使用这些数据库表明，所提出的方法可以将数据准确分类为具有所需特征的三个区域。通过利用这种方法，我们研究了这些结构对 LES 中湍流能量耗散和级联的贡献。结果表明，耗散和向前的能量传递主要发生在平板区域，而向后的能量传递主要发生在压缩管芯区域。在所有三个区域中，都注意到垂直于最大拉伸涡度的方位涡度的强烈生成。然后，我们对 SGS 模型预测负责传递的结构的准确性进行了评估。常系数Smagorinsky模型是表示前向传递的精确模型。在动态Smagorinsky模型（DSM）中，应变对模型的影响减小，并且对负责能量传递的结构的预测精度显着降低。这些SGS模型在实际LES中进一步评估。斯马戈林斯基模型对前向传递的估计过高，而对涡流结构演化的预测则很差。 DSM 高估了管芯区域的贡献，并且对耗散结构的预测较差。 SGS 估算模型克服了这些缺点。在更高雷诺数下对本研究中获得的结果进行评估将留待未来的工作。较少的

项目成果

K. Horiuti: "Correlation of the Turbulent Structure and the Generation Mechanis for the Subgrid-scale energy"Journal of Japan Society of Fluid Mechanics (in Japanese). 17. 426-431 (1998)

K. Horiuti：“次网格尺度能量的湍流结构与生成机制的相关性”日本流体力学学会期刊（日文）。

K. Horiuti: "Energy Cascade and Vortex Sheet/tube Structures"Proc. of 1999 Meeting of Japan Society of Fluid Mechanics (in Japanese). 269-270 (1999)

K. Horiuti：“能量级联和涡流片/管结构”Proc。

K. Horiuti: "Coherent Structure and Subgrid-scale Energy Transfer in Turbulence"Proc. of IUTAM Symposium on Geometry an Statistics of Turbulence Hayama Kanagawa, Nov. 1-5. 37-38 (1999)

K. Horiuti：“湍流中的相干结构和次网格尺度能量传输”Proc。

K. Horiuti: "dissipative Structure and Effect of Rotation for Subgrid-scale Models"ERCOFTAC Bulletin Special Issue on Large-Eddy Simulation. (in press). (2000)

K. Horiuti：“次网格尺度模型的耗散结构和旋转效应”ERCOFTAC 公告大涡模拟特刊。

K. Horiuti: "Subgrid-scale Energy Transfer and the SGS models"Proc. of 15th TODAI-SEIKEN NST Symposium, Tokyo Mar. 2 (in Japanese). 63-70 (2000)

K. Horiuti：“次电网规模能源传输和 SGS 模型”Proc。