108 Direct Numerical Simulation of Drag-Reducing Wall-Bounded Turbulent Flow of Viscoelastic Fluid(2)

Abstract

Direct numerical simulation of a zero-pressure gradient drag-reducing turbulent boundary layer of viscoelastic fluids was performed at the momentum-thickness Reynolds number Re_θ_0=500 and Weissenberg number We=25 using constitutive equation models such as the Oldroyd-B, Giesekus (the mobility factor α=0.01, 0.001, 0.0001) and FENE-P models (the extensibility parameter L^2=100, 1000, 10000). It was found that the maximum drag reduction ratio DR(= 45%) for the Giesekus model with α=0.0001 was the largest. In the case of the same elongational viscosity, the drag reduction ratio for the Giesekus model is larger than that for the FENE-P model.