透水床面明渠湍流时空平均特征的大涡模拟与分析

韩旭; 何国建; 方红卫; 符松

doi:10.6052/0459-1879-14-382

透水床面明渠湍流时空平均特征的大涡模拟与分析

doi: 10.6052/0459-1879-14-382

韩旭¹,
何国建^1, ,,
方红卫¹,
符松²

1.
清华大学水利系, 水沙科学与水利水电工程国家重点实验室, 北京100084
2. 清华大学工程力学系, 北京100084

基金项目: 国家自然科学基金资助项目(11372161)和水沙科学与水利水电工程国家重点实验室科研课题(2014-KY-02)资助项目.

详细信息

通讯作者:
何国建,高级工程师,主要研究方向:计算水力学,水环境数值模拟.E-mail:heguojian@tsinghua.edu.cn

中图分类号: TV131.2
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出版历程
- 收稿日期: 2014-12-01
- 修回日期: 2015-07-08
- 刊出日期: 2015-09-18

LARGE-EDDY SIMULATION AND DOUBLE-AVERAGING ANALYSIS OF OPEN-CHANNEL FLOW OVER A PERMEABLE BED

1.
Department of Hydraulic Engineering, Tsinghua University, The State Key Laboratory of Hydro Science and Engineering, Beijing 100084, China
2. School of Aerospace, Tsinghua University, Beijing 100084, China

Funds: The project was supported by the National Natural Science Foundation of China (11372161) and the State Key Laboratory of Hydro-Science and Engineering, MOST, China (2014-KY-02).

摘要

摘要: 基于大涡模拟数据,研究了理想粗糙透水床面明渠湍流的时空平均特性. 考虑到空间异构性,对比分析了不同位置的时空平均流速、雷诺剪应力、构造剪应力、脉动幅度的垂线分布. 结果表明:第一,顶层床面之上,空间异构性的影响较小,不同位置的双平均流速符合类似的对数分布,但由于透水床面影响,卡门常数较不透水床面小;在床面附近,空间异构性影响较大,不同位置的双平均流速分别符合线性分布与多项式分布;在透水河床内部,靠近底层球孔的双平均流速为上部球孔双平均流速的1.55 倍. 第二,床面之上,雷诺剪应力占总剪应力的95% 以上,占有主体地位;床面附近,紊动较大,构造剪应力不能忽略,其值大约占总剪应力的15%.由于流场的各向异性,纵向与垂向的脉动幅度有所差异.
- 湍流 /
- 大涡模拟 /
- 双平均理论 /
- 透水床面
Abstract: This study focuses on the double-averaging (DA) turbulence characteristics of flow over an idealized permeable bed using the large-eddy simulation (LES). To discuss the spatial heterogeneity, the vertical distributions of DA velocity, DA Reynold shear stress (RSS), DA form-induced shear stress (FISS) and turbulence intensities in different positions are analyzed. It is shown that the spatial heterogeneity has a little influence in the upper flow region, and the distribution of DA velocity corresponds to the logarithmic law. The Von Karman constant obtained is significantly less than the normal value because of permeability. In the vicinity of bed, the spatial heterogeneity has a significant effect on the velocity distributions, which match with a polynomial series and a linear series respectively. Within the permeable bed, the peak velocity at lower pore is 1.55 times larger than that at upper pore. Above the crest bed level, the DA Reynolds shear stress is 95% of the total DA shear stress. The DA form-induced shear stress is 15% of the total DA shear stress occurring at the virtual bed level. The distributions of turbulence intensities in different positions show some discrepancies, which result from the spatial heterogeneity.
- turbulence /
- large-eddy simulation /
- double-averaged method /
- permeable bed

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