(440a) Local Arrest of Carbopol Gel in Quasi Two-Dimensional Flow

Many multiphase materials of commercial interest including foams, emulsions and concentrated suspensions exhibit a yielding transition where material response transitions from primarily solid to liquid. In non-viscometric flows, there can also be coexisting regions of solid-like and liquid-like material. We will present new flow visualization experiments of a Carbopol gel between two vertical clear plates. The fluid is injected from a point at the center of the bottom edge and spreads through the channel. Slip at the plates results in a quasi-2D plug flow. Particle tracking is used to measure local transient velocities and transitions in materials response as the fluid moves away from the injection point. Local arrest of the fluid is seen far from injection where the local stresses are insufficient to maintain the liquid-like response in the gel. Flow, gravitational and apparent yield stresses contribute to the evolving shape of the fluid mass as a function of time. These experiments will provide valuable validation data for the development of predictive computational models for flow of fluids with a yielding transition.

Sandia National Laboratories is a multimission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525. SAND2020-3885 A