Accurate Analysis of Turbulence Dynamics using Unstable Periodic Flow

使用不稳定周期流精确分析湍流动力学

基本信息

  • 批准号:
    17340118
  • 负责人:
  • 金额:
    $ 10.29万
  • 依托单位:
  • 依托单位国家:
    日本
  • 项目类别:
    Grant-in-Aid for Scientific Research (B)
  • 财政年份:
    2005
  • 资助国家:
    日本
  • 起止时间:
    2005 至 2007
  • 项目状态:
    已结题

项目摘要

Fluid mixing is one of the most prominent characteristics of turbulence. In order to understand the mixing dynamics and to develop a quantitative description of its statistical properties we performed the unstable-periodic-flow (UPF) analysis of the passive vectors advected in a Couette system. The unrepeatability of turbulence is one of the main causes which make the turbulence research difficult. In contrast the UPF discovered by Kawahara and Kida (2001), which has positive Lyapunof number, repeats exactly the same state for ever. Therefore, by using the UPF, we can calculate the statistics associated with flows as accurately as desired in proportion to the time devoted. We distribute many passive vectors in this UPF, and compare their stretching rate and orientation with the flow structures. It is found that those passive vectors which start at the same position but with different orientation, will align in direction in a finite time (of order of the period of UPF). This suggests th … More at the directional field of passive vectors may be uniquely defined as a function of the time and position of the UPF. We examine then how are those passive vectors that are distributed uniformly in space will rearrange as the time progresses. We divide the flow field into many small cubes, and calculate the statistics of the direction of passive vectors in each cube. The passive vectors are aligned in a line in most of the cubes. On the other hand, there are quite a few cubes in which the directions of passive vectors are aligned in a plane. We confirmed that such planes are parallel to the vorticity vector and that it is caused by the advection due to strong tubular vortices in the flow. The fluid mixing is enhanced around such places where the direction of passive vectors is diverse. The main organized structure in the Couette turbulence is the streamwise vortex, which creates the ejection and sweep regions near the wall boundary. The linear alignment of passive vectors is found in the interior of the streamwise vortices as well as in the ejection region. The planar distribution, on the other hand, is observed in the periphery of the streamwise vortices and in the sweep region. Such correspondence between the directional distribution of passive vectors and the flow structure depends on the near-past (between the present time and the past about a half of the period of UPF). The passive vectors lose their memory in the characteristic time of the turbulence. This is of essential importance in considering turbulence mixing and in developing turbulence model. Less
流体混合是湍流最突出的特征之一。为了理解混合动力学并为其统计属性进行定量描述,我们对COUETTE系统中高级的被动向量进行了不稳定的周期流(UPF)分析。湍流的不可重复性是使湍流研究变得困难的主要原因之一。相比之下,Kawahara和Kida(2001)发现的UPF(具有积极的Lyapunof数字)永远是完全相同的状态。因此,通过使用UPF,我们可以根据部署时间成比例地计算与所需的流量相关的统计信息。我们在此UPF中分发了许多被动向量,并将其拉伸速率和方向与流量结构进行比较。发现那些从相同位置但以不同方向开始的被动向量将在有限的时间(UPF期间的顺序)对准方向。这表明……在被动矢量的方向场上,可以唯一地定义为UPF的时间和位置的函数。然后,我们检查那些在空间中均匀分布的被动向量将如何随着时间的流逝而重新排列。我们将流场分为许多小立方体,并计算每个立方体中被动向量方向的统计数据。被动向量在大多数立方体中都在一条线中对齐。另一方面,有很多立方体将被动向量的方向对齐在平面中。我们证实了这种平面与涡旋矢量平行,并且由于流动中强的管状涡流而引起的冒险引起的。在被动矢量为潜水员方向的地方周围,流体混合得到了增强。 COUETTE湍流中的主要组织结构是流向涡流,它在壁界附近产生了弹出和甜区。被动矢量的线性比对在流向涡旋的内部以及射血区域中。另一方面,在流向涡流的外围和扫地区域中观察到平面分布。被动矢量的方向分布与流量结构之间的对应关系取决于接近速度(当前时间和过去的大约UPF周期的一半)。在湍流的特征时期,被动向量失去了记忆。这对于考虑湍流混合和发展湍流模型至关重要。较少的

项目成果

期刊论文数量(0)
专著数量(0)
科研奖励数量(0)
会议论文数量(0)
专利数量(0)
Helical flow structure in a precessing sphere
进动球体中的螺旋流结构
  • DOI:
  • 发表时间:
    2008
  • 期刊:
  • 影响因子:
    0
  • 作者:
    S. Kida;K. Nakayama and N. Honda;S. Kida and K. Nakayama
  • 通讯作者:
    S. Kida and K. Nakayama
Persistent Stagnation Points and Turbulent Clustering of Inertial Particles
惯性粒子的持续驻点和湍流团聚
Energy dissipation in spiral vortex layers wrapped around straight vortex tube
缠绕直涡流管的螺旋涡流层的能量耗散
  • DOI:
  • 发表时间:
    2005
  • 期刊:
  • 影响因子:
    0
  • 作者:
    G.;Kawahara;河原源太;後藤 晋;渡部 威;木田重雄;L.Chen;S.Goto;J.C.Vassilicos;G.Kawahara;G.Kawahara
  • 通讯作者:
    G.Kawahara
Laminarization of minimal plane Couette flow: Going beyond the basin of attraction of turbulence
最小平面库埃特流的层化:超越湍流吸引盆
  • DOI:
  • 发表时间:
    2005
  • 期刊:
  • 影响因子:
    0
  • 作者:
    木田重雄;渡部 威;田谷貴男;L.van Veen;G. Kawahara
  • 通讯作者:
    G. Kawahara
不安定周期流によるクエット乱流の混合解析
不稳定周期流引起的库埃特湍流的混合分析
  • DOI:
  • 发表时间:
    2007
  • 期刊:
  • 影响因子:
    0
  • 作者:
    田谷貴男;木田重雄
  • 通讯作者:
    木田重雄
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KIDA Shigeo其他文献

KIDA Shigeo的其他文献

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{{ truncateString('KIDA Shigeo', 18)}}的其他基金

Fundamental Properties of Flows in a Precessing Sphere
进动球内流动的基本性质
  • 批准号:
    24540416
  • 财政年份:
    2012
  • 资助金额:
    $ 10.29万
  • 项目类别:
    Grant-in-Aid for Scientific Research (C)
Statistics of stretching of fluid lines and surfaces, and turbulent mixing
流体线和表面的拉伸以及湍流混合的统计
  • 批准号:
    14540385
  • 财政年份:
    2002
  • 资助金额:
    $ 10.29万
  • 项目类别:
    Grant-in-Aid for Scientific Research (C)
Structure and Dynamics of Turbulent Elementary Vortices
湍流基本涡的结构和动力学
  • 批准号:
    12125204
  • 财政年份:
    2000
  • 资助金额:
    $ 10.29万
  • 项目类别:
    Grant-in-Aid for Scientific Research on Priority Areas
Turbulent Elementary Votrices and New Development in Theory, Predicition, and control of Turbulence
湍流初等涡流及湍流理论、预测和控制的新进展
  • 批准号:
    12125101
  • 财政年份:
    2000
  • 资助金额:
    $ 10.29万
  • 项目类别:
    Grant-in-Aid for Scientific Research on Priority Areas
Theree-dimensional dynamical structure of turbulence vortices Visualization and dynamics
湍流涡旋三维动力学结构可视化与动力学
  • 批准号:
    11837022
  • 财政年份:
    1999
  • 资助金额:
    $ 10.29万
  • 项目类别:
    Grant-in-Aid for Scientific Research (C)
Study of Mechanism of MHD dynamo-Toward Understanding of Geodynamo-
MHD发电机机理研究-了解地球发电机-
  • 批准号:
    07640532
  • 财政年份:
    1995
  • 资助金额:
    $ 10.29万
  • 项目类别:
    Grant-in-Aid for Scientific Research (C)
Statistical Law and Energy Transfer Mechanism in Turbulence
湍流中的统计规律与能量传递机制
  • 批准号:
    03452053
  • 财政年份:
    1991
  • 资助金额:
    $ 10.29万
  • 项目类别:
    Grant-in-Aid for General Scientific Research (B)
Regulation of Metal Complexes by Ligands
配体对金属配合物的调节
  • 批准号:
    63470041
  • 财政年份:
    1988
  • 资助金额:
    $ 10.29万
  • 项目类别:
    Grant-in-Aid for General Scientific Research (B)
Small-Scale Structure of Turbulence
小尺度湍流结构
  • 批准号:
    61540279
  • 财政年份:
    1986
  • 资助金额:
    $ 10.29万
  • 项目类别:
    Grant-in-Aid for General Scientific Research (C)

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Erfassung der makroskopischen Strömungseigenschaften und zellulären Migration der Blutströmung im Couette-System mittels Xenon-NMR-Flussbildgebung und -Spektroskopie
使用氙核磁共振流动成像和光谱检测 Couette 系统中血流的宏观流动特性和细胞迁移
  • 批准号:
    32316112
  • 财政年份:
    2007
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Comprehensive Research Toward the Global Theory for the System of Nonlinear Partial Differential Equations
非线性偏微分方程组整体理论的综合研究
  • 批准号:
    10304012
  • 财政年份:
    1998
  • 资助金额:
    $ 10.29万
  • 项目类别:
    Grant-in-Aid for Scientific Research (A).
Blood damage and turbulence: in vitro study of the turbulence-induced hemolysis in a Taylor-Couette-System
血液损伤和湍流:Taylor-Couette 系统中湍流引起的溶血的体外研究
  • 批准号:
    507267166
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