A study from Sujit Datta's lab, led by graduate student Christopher Browne, found that a promising class of cleaning solutions behave in ways that both confound traditional fluid models and explain their usefulness to remediation efforts. Published 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 contain microscopic polymer strands that act like springs as they move through porous rocks. For reasons scientists are only beginning to understand, those springs can create tiny eddies in the pores, disturbing the flow and dislodging contaminants from the subterranean nooks and crannies. Browne's paper shows that when pores are close enough together, the eddies synchronize across spaces and the effects become stronger. The researchers call it a bistability, referring to the two possible states of equilibrium. Bistability can be found throughout the physical world, in everything from light switches to cell division. Previous work had assumed there was only a single state in the structure of these fluids' flow through pores.
Read more at Princeton University
Image: Researchers from Princeton cracked a decades-old puzzle in fluid dynamics, showing why specialized polymer fluids flush contaminants from groundwater aquifers in some conditions but not others. The work will help engineers control cleanup efforts in sensitive environments. Image courtesy of the researchers