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arXiv 1503.07374physics.flu-dyn
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非结构网格上的离散统一气体动力学格式

Discrete unified gas kinetic scheme on unstructured meshes

Lianhua Zhu, Zhaoli Guo, Kun Xu

摘要:

最近提出的离散统一气体动力学格式(DUGKS)是求解Boltzmann模型方程确定性解的有限体积方法,具有渐近保持性质。在DUGKS中,分布函数的数值通量是使用非分裂方法从玻尔兹曼模型方程的局部数值解确定的。该方法的时间步长和网格分辨率不受分子碰撞时间和平均自由程的限制,为了证明该方法在实际问题中的应用能力,本文将其推广到任意非结构网格。进行了几个实验的内部和外部流动,其中包括空腔流动范围从连续到自由分子制度,多尺度流动之间的两个连接的空腔与压力比为10000,和高速流动的滑移和过渡制度的圆柱。数值结果表明了DUGKS方法在模拟多尺度流动问题中的有效性。

英文摘要:

The recently proposed discrete unified gas kinetic scheme (DUGKS) is a finite volume method for deterministic solution of the Boltzmann model equation with asymptotic preserving property. In DUGKS, the numerical flux of the distribution function is determined from a local numerical solution of the Boltzmann model equation using an unsplitting approach. The time step and mesh resolution are not restricted by the molecular collision time and mean free path. To demonstrate the capacity of DUGKS in practical problems, this paper extends the DUGKS to arbitrary unstructured meshes. Several tests of both internal and external flows are performed, which include the cavity flow ranging from continuum to free molecular regimes, a multiscale flow between two connected cavities with a pressure ratio of 10000, and a high speed flow over a cylinder in slip and transitional regimes. The numerical results demonstrate the effectiveness of the DUGKS in simulating multiscale flow problems.

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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