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| The subcritical transition from laminar to turbulence in flows such as pipe flow, channel flow, Couette flows is one of the classical puzzles of hydrodynamics and is currently an area of intense research. The onset of turbulence in such flows is usually connected with the spatiotemporal dynamics of isolated patches of disordered fluid motion surrounded by more quiescent (laminar) flow. Physical scenarios for the spontaneous spatial localisation of the turbulent fluctuations are still lacking and there is hope that low-order models can shed light on this problem. In this talk I will first give an overview of subcritical transitional flows, focusing both on the local (at the scale of an elementary sub-unit of turbulence) and the global (i.e. spatially extended) dynamics. Next I will demonstrate the strong analogies between localised turbulence and the chimera states emerging in arrays of one- and two-dimensional identical non-locally (attractively) coupled oscillators, where the laminar flow is interpreted as the only possible fully synchronised state: spatial localisation of course but also fractal basin boundaries, scale separation and time-averaged properties. |
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