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首页> 外文期刊>Aerospace science and technology >Detached-eddy simulation of flow past a pitching NACA 0015 airfoil with pulsed actuation
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Detached-eddy simulation of flow past a pitching NACA 0015 airfoil with pulsed actuation

机译：通过脉冲驱动的俯仰NACA 0015翼型流的分离涡模拟

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摘要

This study conducted Detached-Eddy Simulations (DES) of actively controlled flow over a 0.35 m chord NACA0015 airfoil at an incidence angle of 11 degrees and a chord Reynolds number of I million. The uncontrolled, natural flow were simulated by using DES-type methods, with a comparison of different underlying RANS models and subgrid-scale stress models in LES mode. Results from these computations were compared with experimental observations, enabling their reliable assessment through the detailed investigation of the Reynolds stresses as well as the separation and reattachment. It was found that among all five DES-type methods, only the Spalart-Allmaras-based Improved Delayed DES (IDDES-SA) captured the separation point as measured in the experiments. The classical vortex-shedding and the shear-layer flapping modes for airfoil flows with shallow separation were also extracted from the IDDE-SA results by using Dynamic Mode Decomposition. With better understanding of unsteady flow features, effective control practices were illustrated. The pulsed blowing actuation was adopted according to the experimental settings. The flow-field around jet orifices was resolved, instead of the use of actuation boundary conditions. It was found that for all actuation frequencies investigated in this article, the saturation of lift-to-drag ratio was yielded already at intermediate momentum coefficients, two-fifths of the actuation amplitude used in the experiment; the optimal actuation frequency was 0.6 among all cases, consistent with the dominant frequency of the baseline flow. The suppression of separation bubble led to a maximum lift-to-drag ratio enhancement of 194%, as well as a sharp decrease of all Reynolds stress components. To further reduce the strong unsteadiness introduced by excitation, a phase shift among jet orifices was applied and evaluated. The pulsed blowing with the jet orifices in an anti-phased manner was found to be very effective to damp the fluctuations of the lift around its mean value, though it led to a small decrease in mean lift. (C) 2017 Elsevier Masson SAS. All rights reserved.
机译：这项研究在0.35 m弦NACA0015翼型上以11度的入射角和100万弦雷诺数进行了主动涡流的分离涡流模拟（DES）。通过使用DES类型的方法模拟了不受控制的自然流动，并比较了LES模式下不同的基础RANS模型和亚网格规模应力模型。将这些计算的结果与实验观察结果进行比较，从而可以通过对雷诺应力以及分离和重新附着的详细研究来对其进行可靠的评估。发现在所有五种DES类型方法中，只有基于Spalart-Allmaras的改进延迟DES（IDDES-SA）捕获了实验中测量的分离点。通过使用动态模式分解，从IDDE-SA结果中也提取了浅层翼型流动的经典涡流脱落和剪切层扑动模式。通过更好地了解非稳态流动特征，可以说明有效的控制方法。根据实验设置采用脉冲吹气驱动。解决了射流孔周围的流场，而不是使用驱动边界条件。结果发现，对于本文研究的所有驱动频率，升阻比已经达到中间动量系数时的饱和，该动量系数是实验中使用的五分之二。在所有情况下，最佳致动频率为0.6，与基线流量的主导频率一致。分离气泡的抑制导致最大升力比提高194％，并且所有雷诺应力分量均急剧下降。为了进一步减少激发引起的强烈不稳定性，对射流孔之间的相移进行了评估。发现以反相的方式用射流孔口进行脉冲吹气非常有效地抑制了升程在其平均值附近的波动，尽管它导致平均升程略有下降。 （C）2017 Elsevier Masson SAS。版权所有。

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  • 来源
    《Aerospace science and technology》 |2017年第10期|123-135|共13页
  • 作者

    Wang Liang; Fu Song;

  • 作者单位

    Tsinghua Univ, Beijing 100084, Peoples R China;

    Tsinghua Univ, Beijing 100084, Peoples R China;

  • 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
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