OPTIMAL LINEAR PERTURBATIONS IN HARTMANN CHANNEL FLOW: THE INFLUENCE OF WALLS AND MAGNETIC DAMPING
OPTIMAL LINEAR PERTURBATIONS IN HARTMANN CHANNEL FLOW: THE INFLUENCE OF WALLS AND MAGNETIC DAMPING
复制标题
哈特曼通道流中的最佳线性扰动：壁和磁阻尼的影响
DOI：
10.22364/mhd.51.2.6
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发表时间：
2015-04-01
影响因子：
0.7
通讯作者：
Boeck, T.
中科院分区：
文献类型：
--
作者：
Dong, S.;Krasnov, D.;Boeck, T.
本文研究了在中低哈特曼数下，哈特曼槽道流中最佳线性扰动的瞬态放大。这些扰动是与流向无关的涡。它们发展成条纹，这对于亚临界过渡到湍流是很重要的。通过比较反对称和对称扰动，研究了相对通道壁的影响。这两种类型的微扰之间的能量放大差异随着哈特曼数的增加而迅速减小。此外，哈特曼流中的能量放大接近于渐近吸力边界层中的能量放大，即扰动的磁阻尼对瞬态增长的影响很小。
The transient amplification of optimal linear perturbations in Hartmann channel flow is studied at low and moderate Hartmann numbers. These perturbations are streamwise-independent vortices. They develop into streaks, which are important for subcritical transition to turbulence. The influence of the opposite channel wall is examined by comparing antisymmetric and symmetric perturbations. Differences in energy amplification between these two types of perturbations decrease rapidly with the Hartmann number. Moreover, the energy amplification in Hartmann flow is close to that in an asymptotic suction boundary layer, i.e. the magnetic damping of perturbations has only a weak effect on transient growth.