Shi Liang, Hof Björn, Tilgner Andreas
Max Planck Institute for Dynamics and Self-Organization, 37077 Göttingen, Germany and Institute of Geophysics, University of Göttingen, 37077 Göttingen, Germany.
Max Planck Institute for Dynamics and Self-Organization, 37077 Göttingen, Germany and IST Austria, 3400 Klosterneuburg, Austria.
Phys Rev E Stat Nonlin Soft Matter Phys. 2014 Jan;89(1):013001. doi: 10.1103/PhysRevE.89.013001. Epub 2014 Jan 6.
Coriolis force effects on shear flows are important in geophysical and astrophysical contexts. We report a study on the linear stability and the transient energy growth of the plane Couette flow with system rotation perpendicular to the shear direction. External rotation causes linear instability. At small rotation rates, the onset of linear instability scales inversely with the rotation rate and the optimal transient growth in the linearly stable region is slightly enhanced ∼Re2. The corresponding optimal initial perturbations are characterized by roll structures inclined in the streamwise direction and are twisted under external rotation. At large rotation rates, the transient growth is significantly inhibited and hence linear stability analysis is a reliable indicator for instability.
科里奥利力对剪切流的影响在地球物理和天体物理环境中很重要。我们报告了一项关于平面库埃特流线性稳定性和瞬态能量增长的研究，系统旋转方向垂直于剪切方向。外部旋转会导致线性不稳定。在小旋转速率下，线性不稳定的起始与旋转速率成反比，并且线性稳定区域内的最优瞬态增长略有增强，约为Re2。相应的最优初始扰动的特征是沿流向倾斜的滚动结构，并且在外部旋转下会发生扭曲。在大旋转速率下，瞬态增长受到显著抑制，因此线性稳定性分析是不稳定性的可靠指标。
