Space-time structures of rotating flows

To analyse basic features of rotating flows, a fluid enclosed in a cylindrical container, where fluid motion is created by rotation of the end wall, is studied. Owing to the centrifugal force, a strong vortex core is formed along the centre of the container. Direct numerical simulations and spatio-temporal analysis, using the Proper Orthogonal Decomposition (POD) technique, reveal that vortex breakdown may take place and that the temporal transition scenario is accomplished by a complicated dynamic behaviour, with the formation of travelling waves along the vortex core. Studies of both axisymmetric flow and the 3-dimensional symmetry-breakdown have been performed.