Hostname: page-component-586b7cd67f-2brh9 Total loading time: 0 Render date: 2024-12-04T04:22:04.752Z Has data issue: false hasContentIssue false

Direct numerical simulation of polymer-induced drag reduction in turbulent boundary layer flow of inhomogeneous polymer solutions

Published online by Cambridge University Press:  05 October 2006

COSTAS D. DIMITROPOULOS
Affiliation:
Department of Mechanical Engineering, Stanford University, Stanford, CA 94305, USA Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA Center for Turbulence Research, Stanford University, Stanford, CA 94305, USA
YVES DUBIEF
Affiliation:
Department of Mechanical Engineering, Stanford University, Stanford, CA 94305, USA Center for Turbulence Research, Stanford University, Stanford, CA 94305, USA
ERIC S. G. SHAQFEH
Affiliation:
Department of Mechanical Engineering, Stanford University, Stanford, CA 94305, USA Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA
PARVIZ MOIN
Affiliation:
Department of Mechanical Engineering, Stanford University, Stanford, CA 94305, USA Center for Turbulence Research, Stanford University, Stanford, CA 94305, USA

Abstract

Skin-friction drag reduction in turbulent boundary layer flow of inhomogeneous polymer solutions is investigated using direct numerical simulations. A continuum constitutive model (FENE-P) accounting for the effects of polymer microstructure and concentration is used to describe the effect of viscoelasticity. The evolution of wall friction along the streamwise direction is a function of the dynamics of the polymer distribution in the boundary layer. It is observed that polymer transport decreases drag reduction downstream compared to the homogeneous case. The fluctuations of polymer concentration are anti-correlated with those of the streamwise velocity. Concentration is largest in the low-speed streaks. The physical process creating this effect is primarily that of dilution of the high-speed streaks, where due to the local turbulence structure the dispersion of polymer is strongest. Thus, the polymer-induced drag reduction phenomenon is sustained primarily in the vicinity of the low-speed streaks where the injected polymer additive is most effective.

Type
Papers
Copyright
© 2006 Cambridge University Press

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)