Drag reduction by polymers in turbulent wall-bounded flows exhibits universal and non-universal aspects. The universal maximal moan-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 Re, concentration of polymer cp and the degree of polymerization N p. We explain the mechanism of saturation stemming from the finiteness of extensibility of the polymers, predict its dependence on c p and N in the limit of small cp and large Re, and present the excellent comparison of our predictions to experiments on drag reduction by DNA.
Benzi, R., L'Vov, V., Procaccia, I., Tiberkevich, V. (2004). Saturation of turbulent drag reduction in dilute polymer solutions. EUROPHYSICS LETTERS, 68(6), 825-831 [10.1209/epl/i2004-10282-6].
Saturation of turbulent drag reduction in dilute polymer solutions
BENZI, ROBERTO;
2004-01-01
Abstract
Drag reduction by polymers in turbulent wall-bounded flows exhibits universal and non-universal aspects. The universal maximal moan-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 Re, concentration of polymer cp and the degree of polymerization N p. We explain the mechanism of saturation stemming from the finiteness of extensibility of the polymers, predict its dependence on c p and N in the limit of small cp and large Re, and present the excellent comparison of our predictions to experiments on drag reduction by DNA.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
