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  • Letter
  • Open Access

Experimental evidence for invariant solutions mediating transitions from metastable turbulent regimes

B. Vishnu Kiran, Rajath Kashyap, and Balachandra Suri*

  • *Contact author: balachandra@iisc.ac.in
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Phys. Rev. Research 8, L012019 – Published 22 January, 2026

DOI: https://doi.org/10.1103/v3n3-198d

Abstract

We present direct experimental evidence for turbulence visiting the neighborhoods of simple invariant solutions in phase space, immediately preceding and during rapid transitions between metastable flow regimes characterized by opposite large-scale circulations. Specifically, we identify the dynamical signature of an unstable time-periodic orbit that foreshadows these transitions, as well as brief visits to the neighborhoods of unstable equilibria during the transitions. Through direct numerical simulation of the flow, we show that these equilibria are edge states that reside on the boundary separating the two metastable regimes in phase space. Finally, recognizing turbulence approaching the unstable periodic orbit as a precursor, we predict and suppress imminent regime transitions through real-time closed-loop control in experiments.

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Phys. Rev. Research 8, L012019– Published 22 January, 2026
  • Received 10 August 2025
  • Accepted 15 December 2025
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