Stratified Taylor–Couette flow: nonlinear dynamics

A series of experiments on stratified Taylor–Couette flow in short aspect ratio wide-gap annuli found an intriguing and not-well-understood dynamics: nonlinear coherent structures appearing disappearing periodically, along with density layering reminiscent staircase profiles. detailed numerical study is presented the dynamics near onset instability this setting, which explains most characteristics experiments. The simulations show that centrifugal boundary layer inner rotating cylinder produces jets angular momentum forming Taylor cells are compressed axially due to strong stratification. These not axisymmetric from onset, but fact two sets displaced meet localized azimuthal defect regions where patched together; whole structure a wave wavenumber $m=1$ . presence endwalls annulus critical for understanding dynamics. Their impact cannot be accounted idealized periodic models. Another key ingredient role played by symmetries system. Although axial reflection symmetry weakly broken buoyancy effects, following there various branches solutions corresponding different ways system's may broken.