# Critical-Layer Structures and Mechanisms in Elastoinertial Turbulence.

@article{Shekar2018CriticalLayerSA, title={Critical-Layer Structures and Mechanisms in Elastoinertial Turbulence.}, author={Ashwin Shekar and R. M. McMullen and Sung-Ning Wang and Beverley J. McKeon and Michael D. Graham}, journal={Physical review letters}, year={2018}, volume={122 12}, pages={ 124503 } }

Simulations of elastoinertial turbulence (EIT) of a polymer solution at low Reynolds number are shown to display localized polymer stretch fluctuations. These are very similar to structures arising from linear stability (Tollmien-Schlichting modes) and resolvent analyses, i.e., critical-layer structures localized where the mean fluid velocity equals the wave speed. Computations of self-sustained nonlinear Tollmien-Schlichting waves reveal that the critical layer exhibits stagnation points that…

## 51 Citations

### ELASTOINERTIAL TURBULENCE AND CONNECTIONS TO LINEAR MECHANISMS

- Physics
- 2019

One of the most puzzling and dramatic phenomena in non-Newtonian flow is the substantial reduction of turbulent energy dissipation (drag) that occurs when a small amount of a long-chain polymer is…

### Tollmien-Schlichting route to elastoinertial turbulence in channel flow

- PhysicsPhysical Review Fluids
- 2021

Direct simulations of two-dimensional channel flow of a viscoelastic fluid have revealed the existence of a family of Tollmien-Schlichting (TS) attractors that is nonlinearly self-sustained by…

### First coherent structure in elasto-inertial turbulence

- Physics, EngineeringPhysical Review Fluids
- 2022

Two dimensional channel flow simulations of FENE-P fluid in the elasto-inertial turbulence regime reveal distinct regimes ranging from chaos to a steady travelling wave which takes the form of an…

### Effect of polymer-stress diffusion in the numerical simulation of elastic turbulence

- PhysicsJournal of Fluid Mechanics
- 2019

Elastic turbulence is a chaotic regime that emerges in polymer solutions at low Reynolds numbers. A common way to ensure stability in numerical simulations of polymer solutions is to add artificially…

### Self-sustained elastoinertial Tollmien–Schlichting waves

- PhysicsJournal of Fluid Mechanics
- 2020

Direct simulations of two-dimensional plane channel flow of a viscoelastic fluid at Reynolds number $Re=3000$ reveal the existence of a family of attractors whose structure closely resembles the…

### Linear stability analysis of purely elastic travelling wave solutions in pressure driven channel flows

- Physics
- 2022

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…

### Spatio-temporal Signatures of Elasto-inertial Turbulence in Viscoelastic Planar Jets

- Physics, Engineering
- 2022

The interplay between viscoelasticity and inertia in dilute polymer solutions at high deformation rates can result in inertio-elastic instabilities. The nonlinear evolution of these instabilities…

### Purely elastic linear instabilities in parallel shear flows with free-slip boundary conditions

- MathematicsJournal of Fluid Mechanics
- 2021

Abstract We perform a linear stability analysis of viscoelastic plane Couette and plane Poiseuille flows with free-slip boundary conditions. The fluid is described by the Oldroyd-B constitutive…

### Experimental observation of the origin and structure of elastoinertial turbulence

- PhysicsProceedings of the National Academy of Sciences
- 2021

The origin of EIT is determined in experiments and it is demonstrated that characteristic EIT structures can be detected across an unexpectedly wide range of parameters, suggesting that EIT plays as dominant a role in high-shear viscoelastic flows as ordinary turbulence does in high -inertia Newtonian flows.

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