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arXiv 1202.6074physics.flu-dynnlin.CG
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离散速度Boltzmann方程的惯性标架独立强迫:滤波Turbulence模拟的意义

Inertial Frame Independent Forcing for Discrete Velocity Boltzmann Equation: Implications for Filtered Turbulence Simulation

Kannan N. Premnath, Sanjoy Banerjee

摘要:

我们提出了一个系统的推导中心矩格子玻尔兹曼方程的基础上,严格保持伽利略不变性的力量来模拟惯性系独立的流场的模型。在这方面,中心的时刻,即移动的局部流体速度,格子玻尔兹曼方程的离散源项的时刻是通过匹配的连续的完整的玻尔兹曼方程的各种订单。这导致了给定阶次的源项的中心矩与分布函数和低阶源的中心矩的分量之间的精确的分层恒等式。然后,由于适当地选择矩的正交基,从精确的逆变换获得速度空间中的相应源项。此外,这种基于中心矩的动力学模型进一步扩展,将减少压缩性的影响,以代表不可压缩流。此外,对于全部或任何尺度子集或其平均行为的流体湍流的描述和模拟应保持独立于任何惯性参考系。因此,基于上述公式,一个新的方法在格子Boltzmann框架,将湍流模型模拟伽利略不变的统计平均或过滤湍流流体运动进行了讨论。

英文摘要:

We present a systematic derivation of a model based on the central moment lattice Boltzmann equation that rigorously maintains Galilean invariance of forces to simulate inertial frame independent flow fields. In this regard, the central moments, i.e. moments shifted by the local fluid velocity, of the discrete source terms of the lattice Boltzmann equation are obtained by matching those of the continuous full Boltzmann equation of various orders. This results in an exact hierarchical identity between the central moments of the source terms of a given order and the components of the central moments of the distribution functions and sources of lower orders. The corresponding source terms in velocity space are then obtained from an exact inverse transformation due to a suitable choice of orthogonal basis for moments. Furthermore, such a central moment based kinetic model is further extended by incorporating reduced compressibility effects to represent incompressible flow. Moreover, the description and simulation of fluid turbulence for full or any subset of scales or their averaged behavior should remain independent of any inertial frame of reference. Thus, based on the above formulation, a new approach in lattice Boltzmann framework to incorporate turbulence models for simulation of Galilean invariant statistical averaged or filtered turbulent fluid motion is discussed.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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