HYDRODYNAMIC RESISTANCE DUE TO POLYMER-INDUCED ELASTIC TURBULENCE IN MICROFLUIDIC SERPENTINE FLOWS

It has been shown that viscoelastic curvilinear flows transition to turbulence in the limit of diminishing Reynolds numbers (Re → 0) with the onset determined by a critical Weissenberg number (Wic). Serpentine microfluidic geometries have been used to characterize such flows, however, the pressure drop-flow rate dynamics during elastic turbulence is still unexplored. To quantify the hydrodynamic resistance due to elastic turbulence, we map the pressure drop versus flow rate relationship due to elastic turbulence using the iCapillary technique. The instability was investigated for high molecular weight poly ethylene oxide in aqueous-glycerol solvents and a scaling relationship with a saturation plateau was observed for different solvent viscosities based on normalized solution driving pressure with respect to the solvent (ΔP/ ΔP_sol) and plotting against the Weissenberg number. Additionally, Lagrangian representation of the flow was done with digital holography microscopy and CFD simulations were used to analyze deviations from simple shear thinning flows. Thus, we report the first known characterization of flow resistance due to elastic turbulence. The flow resistance relations may provide new insights for structural characterization of polymeric and biofluids.