Manchester Centre for Nonlinear Dynamics

The Manchester Centre for Nonlinear Dynamics is comprised of researchers from the School of Mathematics and the School of Physics and Astronomy at the University of Manchester. Research within the group is based upon the application of a combined approach of theoretical modelling, computation and detailed quantitative experimental investigations of nonlinear phenomena.

Granular jets and hydraulic jumps on an inclined planeMulti-component particle-size segregation in shallow granular avalanchesGravity-driven granular free-surface flow around a circular cylinderRaleigh-Taylor instability in a finite cylinderParticle-size segregation in dense granular avalanchesUnderlying asymmetry within particle size segregationSegregation induced finger formation in granular free-surface flows

Latest News: Work at the MCND on the curling of ribbons has been featured in a BBC News article. For more details see Anne Juel's site or our paper in PNAS.

Features

A symmetry breaking pattern switching phenomenon is observed in 2D granular media under compression. When the undeformed configuration on the left is compressed, rigid cylinders (white) form pairs, resulting from the buckling of columns of elastic cylinders (purple).

A semi-infinite air finger propagates into an elastic-walled channel initially filled by a viscous fluid. The influence of gravity causes asymmetries in the channel wall shapes and in the thicknesses of the fluid films above and below the finger, leading to a monotonic relationship between the air pressure and finger speed.
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Sinuous instability of a confined jet

Left: Passive tracers (shown as streaks) in a confined turbulent momentum jet; middle: corresponding velocity field (arrows) and vorticity field (background) measured using particle image velocimetry; right: schematic of the self-similar unstable sinuous core and alternating side vortices.

Granular fingering and segregation-mobility feedback

A bidisperse granular avalanche exhibits a frontal instability which evolves into levee-channelised 'fingers'.

Airway reopening.

The reopening of pulmonary airways can occur through the propagation of long air finger. If the occluded elastic tube is initially very strongly collapsed, multiple reopening bubbles such as double-tipped (top) or pointed bubbles (bottom) can occur. Read more...