Elastic Alfven waves in elastic turbulence

Abstract

Speed of sound waves in gases and liquids is governed by medium compressibility. There exists another type of non-dispersive waves which speed depends on stress instead of medium elasticity. A well-known example is the Alfven wave propagating, with a speed determined by a magnetic tension, in plasma permeated by a magnetic field. Later, an elastic analog of the Alfven waves has been predicted in a flow of dilute polymer solution, where elastic stress engendered by polymer stretching determines the elastic wave speed. Here, we present quantitative evidence of elastic Alfven waves observed in elastic turbulence of a viscoelastic creeping flow between two obstacles hindering a channel flow. The key finding in the experimental proof is a nonlinear dependence of the elastic wave speed $c_{\mathrm{el}}$ on Weissenberg number $\mathrm{Wi}$, which deviates from the prediction based on a model of linear polymer elasticity.

7 pages, 5 figures

References in corpus (8)

• Elastic turbulence in a polymer solution flow
• Efficient Mixing at low Reynolds numbers using polymer additives
• Elastic turbulence in curvilinear flows of polymer solutions
• Spectra of turbulence in dilute polymer solutions
• On Turbulence of Polymer Solutions
• Elastic waves and transition to elastic turbulence in a two-dimensional viscoelastic Kolmogorov flow
• Elastic wake instabilities in a creeping flow between two obstacles
• Mixing layer instability and vorticity amplification in a creeping viscoelastic flow

Cited by in corpus (15)

• Dynamics of active liquid interfaces
• 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
• Numerical Study of Viscoelastic Upstream Instability
• Elastic turbulence in two-dimensional cross-slot viscoelastic flows
• Preserving large-scale features in simulations of elastic turbulence
• Elastic instability in a straight channel of viscoelastic flow without prearranged perturbations
• Universal coherent structures of elastic turbulence in straight channel with viscoelastic fluid flow
• Re-laminarization of elastic turbulence
• Enhancement of drag and mixing in a dilute solution of rodlike polymers at low Reynolds numbers
• Pressure measurements in an elastically turbulent co-moving Kelvin-Helmholtz-like shear flow inside a straight Hele-Shaw cell
• The broken link between space and time in elastic turbulence