Transient Growth of Ekman-Couette Flow

Abstract

Coriolis force effects on shear flows are important in geophysical and astrophysical contexts. We here 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, ~Re^2. 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.

7 pages, 9 figures

References in corpus (4)

• Hydrodynamic turbulence cannot transport angular momentum effectively in astrophysical disks
• Stability and angular-momentum transport of fluid flows between corotating cylinders
• Scale invariance at the onset of turbulence in Couette flow
• On self-sustaining processes in Rayleigh-stable rotating plane Couette flows and subcritical transition to turbulence in accretion disks