Saturation of turbulent drag reduction in dilute polymer solutions

@article{Benzi2004SaturationOT,
  title={Saturation of turbulent drag reduction in dilute polymer solutions},
  author={Roberto Benzi and Victor S L’vov and Itamar Procaccia and Vasil Tiberkevich},
  journal={EPL},
  year={2004},
  volume={68},
  pages={825-831}
}
Drag reduction by polymers in turbulent wall-bounded flows exhibits universal and non-universal aspects. The universal maximal mean-velocity profile was explained in a recent theory. The saturation of this profile and the crossover back to the Newtonian plug are non-universal, depending on Reynolds number e, concentration of polymer cp and the degree of polymerization Np. We explain the mechanism of saturation stemming from the finiteness of extensibility of the polymers, predict its dependence… 

Figures from this paper

Phenomenology of wall-bounded Newtonian turbulence.

The model offers an analytic description of the profiles of the mean velocity and the correlation functions of velocity fluctuations in the entire boundary region, from the viscous sublayer, through the buffer layer, and further into the log-law turbulent region.

References

SHOWING 1-8 OF 8 REFERENCES

AIChE J

  • 21, 625
  • 1975

Phys

  • Rev. Lett, 89 088302-1
  • 2002

Drag reduction by a linear viscosity profile.

It is shown, using direct numerical simulations, that a linear viscosity profile indeed reduces the drag in agreement with the theory and in close correspondence with direct simulations of the FENE-P model at the same flow conditions.

Drag reduction by polymers in turbulent channel flows: Energy redistribution between invariant empirical modes.

There is an enhancement of theEnergy containing modes in the viscoelastic flow compared to the Newtonian one; drag reduction is seen in the energy containing modes rather than the dissipative modes, as proposed in some previous theories.

Polymer stress tensor in turbulent shear flows.

It is demonstrated that the influence of the polymers on the balance of energy and momentum can be accurately described by an effective polymer viscosity that is proportional to the cross-stream component of the elastic stress tensor.

Drag reduction by polymers in wall bounded turbulence.

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

Phys

  • Rev. Lett. 78, 239
  • 1997

in Proceedings of the International Congress of Rheology Amsterdam Vol 2

  • 0.135-141
  • 1949