Universal coherent structures of elastic turbulence in straight channel with viscoelastic fluid flow
arXiv:2009.12258
Abstract
In the present study, we investigated flow structures and properties of elastic turbulence in straight 2D channel viscoelastic fluid flow and tested earlier observations. We discovered self-organized cycling process of weakly unstable coherent structures (CSs) of co-existing streaks and stream-wise vortices, with the former being destroyed by Kelvin-Helmholtz-like instability resulting in chaotic structures. The sequence periodically repeats itself leading to stochastically steady state. This self-sustained process (SSP) remarkably resembles one investigated theoretically and experimentally for Newtonian turbulence in straight channel flow. The unexpected new ingredient is the observation of elastic waves, which finds to be critical for existence of CSs and SSP generation due to energy pumping from large to smaller scales preceding sharp power-law decay in elastic turbulence energy spectrum. The reported finding suggests the universality of CSs in transition to turbulence via self-organized cycling (SSP) in linearly stable plane shear flows of both elastic and Newtonian fluids.
arXiv comment13 pages, 6 figures
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Cited by in corpus (5)
- Understanding viscoelastic flow instabilities: Oldroyd-B and beyond
- A continuous pathway between the elasto-inertial and elastic turbulent states in viscoelastic channel flow
- Elastically driven Kelvin-Helmholtz-like instability in planar channel flow
- Coherent structures in plane channel flow of dilute polymer solutions with vanishing inertia
- New directions and perspectives in elastic instability and turbulence in various viscoelastic flow geometries without inertia