Active and hibernating turbulence in drag-reducing plane Couette flows

In this paper we analyze the active and hibernating turbulence in drag-reducing plane Couette flows using direct numerical simulations of the viscoelastic finitely extensible nonlinear elastic model with the Peterlin approximation fluids. The polymer-turbulence interactions are studied from an energetic standpoint for a range of Weissenberg numbers ( from 2 up to 30), fixing the Reynolds number based on the plate velocities at 4000, the viscosity ratio at 0.9, and the maximum polymer molecule extensibility at 100. The qualitative picture that emerges from this investigation is a cyclic mechanism of energy exchange between the polymers and turbulence that drives the flow through an oscillatory behavior.