Secondary energy growth and turbulence suppression in conducting channel flow with streamwise magnetic field
Secondary energy growth and turbulence suppression in conducting channel flow with streamwise magnetic field
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DOI：
10.1063/1.4731293
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发表时间：
2012-07
影响因子：
4.6
通讯作者：
S. Dong;D. Krasnov;T. Boeck
中科院分区：
文献类型：
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作者：
S. Dong;D. Krasnov;T. Boeck
通过分析流向条纹上的二次线性扰动和直接再分层的数值模拟，研究了流向磁场对导电槽道流动的影响。通过最优微扰方法，发现磁阻尼能增加最大放大的二次微扰的流向波长，并降低它们的放大水平。当考虑条纹状基本流的瞬时演化时，在一个依赖于条纹幅度和雷诺数的临界磁相互作用参数下，观察到了二次不稳定性的完全抑制。直接数值模拟中的再透明化发生在相互作用参数低于所考虑的条纹幅度的稳定性计算的临界值时。这些相互作用参数的阈值对雷诺数的依赖关系在模拟和稳定性分析中非常相似。再分层...
The effects of a streamwise magnetic field on conducting channel flow are studied by analyzing secondary linear perturbations evolving on streamwise streaks and by direct numerical simulations of relaminarization. By means of an optimal perturbation approach, magnetic damping is found to increase the streamwise wavelength of the most amplified secondary perturbations and to reduce their amplification level. Complete suppression of secondary instability is observed at a critical magnetic interaction parameter that depends on the streak amplitude and on the Reynolds number when the transient evolution of the streaky basic flow is taken into account. Relaminarization in the direct numerical simulation occurs at lower values of the interaction parameter than the critical values from the stability computations for the streak amplitudes considered. The dependence of these threshold values of the interaction parameters on the Reynolds number is fairly similar between simulations and stability analysis. Relaminar...