LAUSR

The paper presents a direct numerical simulation (DNS) for the drag-reducing channel flow using the Giesekus model with variable parameters. It is assumed that the relaxation time in the constitutive equation is varied depending on the local shear rate. The maximal drag reduction rate is obtained when variable parameters are applied in the Giesekus model at a high Weissenberg number. The Reynolds shear stress is reduced when the Weissenberg number increases. In this case, the turbulence generation and transportation are further weakened and increasingly approach to the values in the experiments.