Research Update - Friction, Fruit, and Flow
Visiting professor Jackie Krim, who is at Duke on sabbatical from North Carolina State University, studies nanoscale tribology, and Duke professor Bob Behringer is an expert on granular and fluid flows. They recently applied their knowledge of the behavior of granular materials in motion to an age-old fruit market conundrum—how to pick a piece of fruit out of a pile without triggering collapse.Krim and Behringer studied and filmed piles of apples, oranges, and onions as one or more pieces of fruit were removed. Among other things, they discovered that increasing the friction of the onions (by peeling them) decreased the likelihood of collapse. “Theorists always thought that friction impacts collapse,” Krim says, “and we devised an experimentally controlled way to prove it, accessible to all who dare try.”To learn more about how friction affects collapse, view Krim and Behringer's article in Physics Today.