低强度磁场作用下Hunt流的稳定性分析

doi:10.16182/j.issn1004731x.joss.17-0301

摘要/Abstract

摘要： 矩形管道内导电流体在磁场作用下的流动稳定性对材料的制备、热核聚变冷却系统的设计和运行均有重要意义。采用非正则模态稳定性分析方法,对Hunt流进行了数值模拟,获得了4种模态下初始扰动的增长特征及空间分布,分析了低强度磁场对流动稳定性的影响。结果表明,哈特曼数Ha较小时,4种模态下的扰动均呈瞬态增长;Ha较大时,4种模态下的扰动出现两种增长模式：类型为模态I、III、IV的扰动仍呈瞬态增长,模态II的扰动呈指数增长,此时流场稳定性与射流有关。

关键词: Hunt流, 稳定性, 非正则模态, 瞬态增长, 指数增长

Abstract: The stability of conducting fluid flow in ducts under magnetic field is vital to materials preparation and the design and operation of thermonuclear fusion cooling system. A model of MHD duct flow which is known as Hunt’s flow is simulated by non-normal mode stability analysis in this study^.. The amplification and distribution of optimal primary perturbations are obtained by solving iteratively the direct and adjoint governing equations with respect of the perturbation variables. Four modes of perturbations with different symmetries in the space are considered, and the effect of the low-intensity magnetic field is also taken into account. The results show that, when the Hartmann number Ha is small, the perturbations in the form of different modes exhibit transient growth. By contrast, when Ha is large, these perturbations behave differently: the perturbations in the form of mode I, III and IV grow transiently; the perturbations of mode II grows exponentially, meanwhile, the flow stability is related to jets.

Key words: Hunt's flow, stability, non-normal mode, transient growth, exponential growth

中图分类号:

O361.5

董帅, 李爽, 叶学民. 低强度磁场作用下Hunt流的稳定性分析[J]. 系统仿真学报, 2019, 31(8): 1605-1616.

Dong Shuai, Li Shuang, Ye Xuemin. Flow Stability of Hunt Flow under Low-intensity Magnetic Field[J]. Journal of System Simulation, 2019, 31(8): 1605-1616.

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