Characterizing purely elastic turbulent flow of a semi-dilute entangled polymer solution in a serpentine channel

Polymer solutions in the semi-dilute regime are of considerable industrial importance. The complex rheological properties such highly viscoelastic fluids and complexity their flow characteristics, especially curved geometries, necessitate a thorough experimental characterization dynamics fluid flows. We apply statistical, spectral, structural analyses to experimentally obtained velocity fields entangled polymer solution serpentine channel fully characterize corresponding flow. Our results show that at high Weissenberg numbers, yet vanishing Reynolds resistance is significantly increased, which indicates emergence purely elastic turbulent Spatial observations statistical analysis temporal features this non-homogeneous, non-Gaussian, anisotropic all scales. Moreover, spectral compared turbulence dilute regime, range present scales excited fluctuations narrower. This partly due entanglement polymers concentration restricts movement, mixed type inherent geometry, can reduce extent stretching and, thus, intensity Furthermore, proper orthogonal decomposition applied directly extract structure reveals activity counter-rotating vortices associated with secondary flow, contribute total kinetic energy