Abstract
Creeping flow of polymeric fluid without inertia exhibits elastic instabilities and elastic turbulence accompanied by drag enhancement due to elastic stress produced by flow-stretched polymers. However, in inertia-dominated flow at high and low fluid elasticity , a reduction in turbulent frictional drag is caused by an intricate competition between inertial and elastic stresses. Here we explore the effect of inertia on the stability of viscoelastic flow in a broad range of control parameters and . We present the stability diagram of observed flow regimes in coordinates and find that the instabilities' onsets show an unexpectedly nonmonotonic dependence on . Further, three distinct regions in the diagram are identified based on . Strikingly, for high-elasticity fluids we discover a complete relaminarization of flow at Reynolds number in the range of 1 to 10, different from a well-known turbulent drag reduction. These counterintuitive effects may be explained by a finite polymer extensibility and a suppression of vorticity at high . Our results call for further theoretical and numerical development to uncover the role of inertial effect on elastic turbulence in a viscoelastic flow.
- Received 29 May 2018
DOI:https://doi.org/10.1103/PhysRevFluids.3.103302
©2018 American Physical Society