# Drag reduction by a linear viscosity profile.

@article{DeAngelis2004DragRB, title={Drag reduction by a linear viscosity profile.}, author={Elisabetta De Angelis and Carlo Massimo Casciola and Victor S L’vov and Anna Pomyalov and Itamar Procaccia and Vasil Tiberkevich}, journal={Physical review. E, Statistical, nonlinear, and soft matter physics}, year={2004}, volume={70 5 Pt 2}, pages={ 055301 } }

Drag reduction by polymers in turbulent flows raises an apparent contradiction: the stretching of the polymers must increase the viscosity, so why is the drag reduced? A recent theory proposed that drag reduction, in agreement with experiments, is consistent with the effective viscosity growing linearly with the distance from the wall. With this self-consistent solution the reduction in the Reynolds stress overwhelms the increase in viscous drag. In this Rapid Communication we show, using…

## 42 Citations

### TURBULENT DRAG REDUCTION BY RIGID POLYMERS

- Engineering
- 2013

Although the phenomenon of the drag reduction has been known for almost half a century, its precise mechanism is not fully understood and still continues to be a fascinating challenge. In recent…

### Turbulent viscosity profile of drag reducing rod-like polymers

- Engineering, PhysicsThe European physical journal. E, Soft matter
- 2018

This work investigates the turbulent drag reduction characteristics of a stiff rod-like polymer for which any effective viscosity changes are only due to the orientation of the polymers, and shows that close to the walls the polymer orientation leads to a reduction of the Reynolds stress and hence to a drag reduction.

### Turbulent drag reduction using fluid spheres

- Physics, EngineeringJournal of Fluid Mechanics
- 2013

Abstract Using direct numerical simulations of turbulent Couette flow, we predict drag reduction in suspensions of neutrally buoyant fluid spheres, of diameter larger than the Kolmogorov length…

### Drag reduction by polymers in wall bounded turbulence.

- PhysicsPhysical review letters
- 2004

The phenomenology of the "maximum drag reduction asymptote" is developed which is the maximum drag reduction attained by polymers in turbulent wall-bounded flows.

### Maximum drag reduction asymptotes and the cross-over to the Newtonian plug

- EngineeringJournal of Fluid Mechanics
- 2006

We employ the full FENE-P model of the hydrodynamics of a dilute polymer solution to derive a theoretical approach to drag reduction in wall-bounded turbulence. We recapture the results of a recent…

### SOME DYNAMICAL FEATURES OF THE TURBULENT FLOW OF A VISCOELASTIC FLUID FOR REDUCED DRAG

- Physics, EngineeringProceeding of Seventh International Symposium on Turbulence and Shear Flow Phenomena
- 2011

It is well known that the addition of minute amounts of long polymer chains to organic solvents, or water, can lead to significant turbulent drag reduction. In the present study, direct numerical…

### Near-wall lubricating layer in drag-reduced flows of rigid polymers

- Engineering
- 2021

The current theories on the mechanism for polymer drag-reduction (DR) are generally applicable for long-chain flexible polymers that form viscoelastic solutions. Rigid polymer solutions that generate…

### Identification and calculation of the universal asymptote for drag reduction by polymers in wall bounded turbulence.

- PhysicsPhysical review letters
- 2005

This insight rationalizes the universality of the MDR and provides a maximum principle which allows an ab initio calculation of the parameters in this law without any viscoelastic experimental input.

### Mechanics and Prediction of Turbulent Drag Reduction with Polymer Additives

- Physics
- 2008

This article provides a review of recent progress in understanding and predicting polymer drag reduction (DR) in turbulent wall-bounded shear flows. The reduction in turbulent friction losses by the…

### Skin-Friction Drag Reduction by Dilute Polymer Solutions in Turbulent Channel Flow.

- Physics
- 2010

Skin-friction drag reduction by dilute polymer solutions is investigated using results from direct numerical simulations (DNS) of homogeneous polymer solutions in turbulent channel flow. Simulations…

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The phenomenology of the "maximum drag reduction asymptote" is developed which is the maximum drag reduction attained by polymers in turbulent wall-bounded flows.

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