3 research outputs found
Geometry of transient chaos in streamwise-localized pipe flow turbulence
In pipes and channels, the onset of turbulence is initially dominated by
localized transients, which lead to sustained turbulence through their
collective dynamics. In the present work, we study the localized turbulence in
pipe flow numerically and elucidate a state space structure that gives rise to
transient chaos. Starting from the basin boundary separating laminar and
turbulent flow, we identify transverse homoclinic orbits, the presence of which
necessitates a homoclinic tangle and chaos. A direct consequence of the
homoclinic tangle is the fractal nature of the laminar-turbulent boundary,
which was conjectured in various earlier studies. By mapping the transverse
intersections between the stable and unstable manifold of a periodic orbit, we
identify the 'gateways' that promote an escape from turbulence.Comment: Accepted for publication in Physical Review Fluids as a Rapid
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