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首页> 外文期刊>International Journal of Heat and Fluid Flow >Evolution of turbulence characteristics from straight to curved pipes
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Evolution of turbulence characteristics from straight to curved pipes

机译：湍流特性从直管到弯管的演变

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摘要

Fully developed, statistically steady turbulent flow in straight and curved pipes at moderate Reynolds numbers is studied in detail using direct numerical simulations (DNS) based on a spectral element discretisation. After the validation of data and setup against existing DNS results, a comparative study of turbulent characteristics at different bulk Reynolds numbers Reb = 5300 and 11,700, and various curvature parameters κ=0, 0.01, 0.1 is presented. In particular, complete Reynolds-stress budgets are reported for the first time. Instantaneous visualisations reveal partial relaminarisation along the inner surface of the curved pipe at the highest curvature, whereas developed turbulence is always maintained at the outer side. The mean flow shows asymmetry in the axial velocity profile and distinct Dean vortices as secondary motions. For strong curvature a distinct bulge appears close to the pipe centre, which has previously been observed in laminar and transitional curved pipes at lower Re_b only. On the other hand, mild curvature allows the interesting observation of a friction factor which is lower than in a straight pipe for the same flow rate. All statistical data, including mean profile, fluctuations and the Reynolds-stress budgets, is available for development and validation of turbulence models in curved geometries.
机译：使用基于频谱元素离散化的直接数值模拟（DNS），对处于中等雷诺数的直管和弯管中的充分发展的统计稳定湍流进行了详细研究。在对数据进行验证并针对现有DNS结果进行设置后，提出了在不同体积雷诺数Reb = 5300和11,700以及各种曲率参数κ= 0、0.01、0.1时湍流特性的比较研究。特别是，首次报告了完整的雷诺应力预算。瞬时可视化显示弯曲管的内表面以最大曲率进行部分再分层，而始终在外侧保持已形成的湍流。平均流量在轴向速度曲线中显示为不对称，并且作为二次运动显示出明显的Dean涡旋。对于大曲率，在靠近管道中心处会出现明显的凸起，以前仅在较低Re_b处的层流和过渡弯曲管道中观察到过。另一方面，对于相同的流量，适度的曲率允许有趣地观察到比直管中更低的摩擦系数。所有统计数据，包括均值轮廓，波动和雷诺应力预算，都可用于开发和验证弯曲几何形状中的湍流模型。

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  • 作者

    A. Noorani; G.K. El Khoury; P. Schlatter;

  • 作者单位

    Linne FLOW Centre and Swedish e-Science Research Centre (SeRC), KTH Mechanics, Royal Institute of Technology, SE-100 44 Stockholm, Sweden;

    Linne FLOW Centre and Swedish e-Science Research Centre (SeRC), KTH Mechanics, Royal Institute of Technology, SE-100 44 Stockholm, Sweden;

    Linne FLOW Centre and Swedish e-Science Research Centre (SeRC), KTH Mechanics, Royal Institute of Technology, SE-100 44 Stockholm, Sweden;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

    Wall turbulence; Pipe flow; Curvature effects; Reynolds-stress budgets; Coiled tube;

    机译：壁湍流;管道流动;曲率效应;雷诺应力预算;盘管;

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