Temporal large eddy simulations of turbulent viscoelastic drag reduction flows

Abstract

We report on temporal large eddy simulations (TLES) of the turbulent channel flow of a dilute polymer solution modeled with the FENE-P (finitely extensible nonlinear elastic in the Peterlin approximation) constitutive equation. The large eddy simulations are based upon an approximate temporal deconvolution method [Pruett et al., Phys. of Fluids, 18, 028104–1, (2006)] for residual Newtonian stress modeling and secondary regularization for unresolved subfilter Newtonian stress. The filtered conformation tensor equation involves deconvolution for stretching and for the nonlinear spring force, as well as secondary regularization. Results are shown at a friction Reynolds number 180 for Weissenberg numbers and molecular extensibilities spanning the moderate to high drag reducing regimes. Excellent agreement is obtained between TLES and direct numerical simulations (DNS) in terms of percent drag reduction prediction. TLES is also able to reproduce the high level of anisotropy of turbulence, which confirms recent findings by Frohnapfel et al. [J. Fluid Mech. 577, 457 (2007)] who present high anisotropy as a general mechanism to obtain significant drag reduction. The TLES model proves itself stable and its overall computational workload some 60 times less than DNS.