Solving a messy problem

Engineering researchers make a media splash with sleek new 'splash-free' urinal design. By Brian Caldwell Faculty of Engineering - Engineering researchers at the University of Waterloo followed their curiosity and called on nature for inspiration for a new urinal design that has attracted internatinal attention by solving the messy problem of splash-back. The long, sleek design all but eliminates splatter on floors and shoes by ensuring the angle at which a urine stream hits the urinal wall doesn't exceed about 30 degrees, a measurement determined via physical experiments and computer modelling. "We found that when a liquid jet or droplet train impacts a rigid surface below a certain critical impinging angle, almost no splatter is generated," the researchers wrote. "Thus, a surface designed to always intersect the urine stream equal to or smaller than the critical angle prevents splash-back." Conducted by a team of professors and students at Waterloo and Weber State University in Utah, the study that produced the new design has made news in multiple languages since the results were presented at a recent American Physical Society conference in Indianapolis. Dr. Zhao Pan , a professor of mechanical and mechatronics engineering at Waterloo who led the project over the course of several years, said the response has been particularly gratifying because much of the work was done by undergraduate students in his lab. "This urinal design project is the best teaching tool I can think of, as it is a daily-life problem that covers numerous topics - including fluid mechanics, sustainability, differential equations, manufacturing and prototyping, art, industrial design, human factors, bio-mechanics and testing," he said.