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Title: Are elasto-inertial and purely elastic turbulence the same state?
Plain: Polymer solutions show chaotic flow both at moderate speeds, where inertia helps, and at vanishing speeds, from elasticity alone. Whether these are two forms of one state is unknown.
Precise: In the $(\mathrm{Re}, \mathrm{Wi}, \beta)$ parameter space of channel or pipe flow of FENE-P or simplified Phan-Thien-Tanner fluids, is there a continuous path from elasto-inertial turbulence at $\mathrm{Re} \sim 10^{3}$ to purely elastic turbulence at $\mathrm{Re} \to 0$ along which the organizing coherent structures (center-mode travelling waves, arrowhead or narwhal states) persist? Answer: yes or no, with the path or the boundary that separates the two.
Settled by: Numerical continuation of coherent states and chaotic attractors across the full Re range for one constitutive model, checked against experiments with matched rheology.
Kind: well-posed
Answer type: yes-no
References: (empty)
Literature status: partially-resolved
Status note: Linear-stability continuation (Khalid, Shankar, Subramanian 2021) and 2024 simulations support a link; 2026 pipe experiments find a change in threshold scaling where inertia vanishes.
Posed since: 2021