Taylor vortices in annular spherical flow at large aspect ratios

Motivated by recent theoretical and experimental work, we numerically investigate spherical Couette flow with a view to obtaining for the first time Taylor vortices at large aspect ratios σ such as 0.38, 0.42, and 0.48. It is found that Taylor vortices can exist, stable or time-dependent, in a range of Reynolds numbers [Re1, Re2] and their formation depends on the aspect ratio, on the imposition of various rotationary conditions on the boundaries, on the history of the flow and on the rate at which energy is transferred into the fluid to its final value. With increasing σ the range [Re1, Re2] manifests a clear tendency to shorten.