Drag reduction by linear viscosity model in turbulent channel flow of polymer solution

A further numerical study of the theory that the drag reduction in the turbulence is related to the viscosity profile growing linearly with the distance from the wall was performed. The constant viscosity in the Navier-Stokes equations was replaced using this viscosity model. Some drag reduction characteristics were shown comparing with Virk's phenomenology. The mean velocity and Reynolds stress profiles are consistent with the experimental and direct numerical simulation results. A drag reduction level of 45% was obtained. It is reasonable for this linear viscosity model to explain the mechanism of turbulence drag reduction in some aspects.