Polymer and surfactant flows through a periodically constricted tube

The flow of three non-Newtonian fluids, comprising polymer and surfactant additives, in a periodically constricted tube (PCT) are experimentally compared. radius the walls is sinusoidal with respect to streamwise direction. fluids aqueous solutions flexible polymers, rigid biopolymers surfactants, which typically used for drag-reduction turbulent flows. Steady shear viscosity measurements demonstrate that shear-thinning, while have Newtonian water-like viscosity. Capillary driven extensional rheology demonstrates only produce elastocapillary thinning. Particle shadow velocimetry measure velocity each within PCT at five Reynolds numbers spanning roughly 0.5 300. Relative flows, exhibit blunt profile. Flexible distinct chevron-shaped contour zones opposing vorticity when Deborah number exceeds 0.1. Using transport equation, it revealed coupled torque. reveals similar features as – those being chevron pattern, finite This observation practical importance since conventional rheometric not capable demonstrating solutions. investigation serves viable geometry showing traits dilute