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Statistical Law and Energy Transfer Mechanism in Turbulence

湍流中的统计规律与能量传递机制

基本信息

批准号：
03452053
负责人：
KIDA Shigeo
金额：
$ 4.48万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1991
资助国家：
日本
起止时间：
1991 至 1993
项目状态：
已结题

项目摘要

1. It was found in the homogeneous isotropic turbulence that the energy transfer through the trial interaction is local in the inertial range but it is nonlocal in the dissipation range. The former agrees with the Kolmogorov theory while the latter may give a useful suggestion to turbulence modelling. The generation, development and breakdown of various vortical structures in a uniformly sheared turbulence were analyzed in terms of the dynamics of the vorticity vector. The relative importance of the mean flow, advection, nonlinear selfinteraction and viscous terms in the energy transfer process was clarified.2. The localized structure in the marginal convection state between two rotating spheres was solved. A new bifurcation branch was found as the Reyleigh number is increased. A bunch of Taylor columns with strong helicity were realized by the direct numerical simulation.3. The mechanism of the energy transfer in a forced compressible turbulence was investigated by analysing the vorticity and density fields. The kinetic energy was divided into the compressible and rotational parts by employing the Helmholtz decomposition. The relative importance of the advection, the baroclinic and the viscous terms in the energy exchange between these components and internal energy was evaluated quantitatively.4. The mechanism of pattern formation in a Rayleigh-Benard convection was clarified by the weakly nonlinear theory.5. The statistical law in the complex Ginzburg-Landau turbulence was explained by the interaction between the fundamental solutions.

1.发现在均质各向同性湍流中，通过试验相互作用的能量传递在惯性范围内是局域的，但在耗散范围内是非局域的。前者与柯尔莫哥洛夫理论一致，后者可能为湍流建模提供有益的建议。从涡度矢量的动力学角度分析了均匀剪切湍流中各种涡结构的产生、发展和破坏。明确了平均流、平流、非线性自相互作用和粘性项在能量传递过程中的相对重要性。 2．解决了两个旋转球体之间边缘对流状态的局域结构。随着瑞利数的增加，发现了一个新的分叉分支。通过直接数值模拟，实现了一组具有强螺旋性的泰勒柱。 3．通过分析涡度场和密度场，研究了强制压缩湍流中的能量传递机制。通过亥姆霍兹分解将动能分为可压缩部分和旋转部分。定量评价了平流项、斜斜项和粘性项在这些成分与内能之间的能量交换中的相对重要性。 4．利用弱非线性理论阐明了瑞利-贝纳德对流的模式形成机制。 5．复杂的金茨堡-朗道湍流中的统计规律可以通过基本解之间的相互作用来解释。