EVENT DETAILS AND ABSTRACT

Title: Transition to turbulence in pipe flow:new aspects of an old problem
Speaker: Bruno Eckhardt
Speaker Info: University of Marburg, Germany
Brief Description:
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Abstract:

Over a hundred years ago Osborne Reynolds studied the transition to turbulence in pipe flow, and documented its dependence on flow speed and perturbation and the structures of the turbulent flow. Theoretical analyses of the problem are made difficult by the fact that the laminar parabolic flow profile is linearly stable for all Reynolds numbers. A combination of modern experiments and direct numerical simulations, model building and a nonlinear dynamics phenomenology has unravelled some of the mysteries of the transition: there are fractal stability boundaries, chaotic saddles, exponential life time distributions and unstable periodic states. Besides the numerical evidence there now is also experimental support for some of the ideas.