Abstract
Recent studies of pressure-driven flows of dilute polymer solutions in straight channels demonstrated the existence of two-dimensional coherent structures that are disconnected from the laminar state and appear through a subcritical bifurcation from infinity. These travelling-wave solutions were suggested to organise the phase-space dynamics of purely elastic and elasto-inertial chaotic channel flows. Here, we consider a wide range of parameters, covering the purely elastic and elasto-inertial cases, and demonstrate that the two-dimensional travelling-wave solutions are unstable when embedded in sufficiently wide three-dimensional domains. Our work demonstrates that studies of purely elastic and elasto-inertial turbulence in straight channels require three-dimensional simulations, and no reliable conclusions can be drawn from studying strictly two-dimensional channel flows.
Original language | English |
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Article number | R1 |
Pages (from-to) | 1-10 |
Number of pages | 10 |
Journal | Journal of Fluid Mechanics |
Volume | 959 |
DOIs | |
Publication status | Published - 15 Mar 2023 |
Keywords / Materials (for Non-textual outputs)
- polymers
- shear-flow instability
- bifurcation