Research from Sujit Datta’s lab, headed by graduate student Christopher Browne, discovered that a promising class of cleaning solutions behave in ways that confound traditional fluid models as well as clarify their usefulness to remediation efforts. Featured on March 2 in the Journal of Fluid Mechanics, the paper helps solve a decades-old puzzle about why these cleaners only work in some conditions.
The fluids comprise microscopic polymer strands that act like springs as they move by porous rocks. For reasons scientists are only starting to understand, these springs can create tiny eddies in the pores, disturbing the circulation and dislodging contaminants from the subterranean nooks and crannies. Browne’s paper shows that when pores are close enough collectively, the eddies synchronize throughout spaces and the results become stronger.
The researchers call it bistability, referring to the two possible states of equilibrium. Bistability will be discovered throughout the physical world, in everything from light switches to cell division. Earlier work had assumed there was solely a single state in the structure of those fluids’ flow via pores.
Polymer fluids could be an efficient tool in cleansing crude oil, mercury, and other contaminants from polluted aquifers. However, not knowing exactly how these fluids work, and not having the ability to predict their results, renders them dangerous in sensitive environments.
Engineers remain cautious of their use because, in some instances, utilizing the wrong resolution could make matters worse. Solving the cleanup problem means getting a closer look at this springy action underground.