New techniques promise better containment of contaminants from environmental disasters
September 8, 2015
Catastrophic oil spills, nuclear power accidents, and erupting volcanoes all share a common thread. They are environmental disasters where the flow of hazardous materials, dispersed by the natural movements of air and/or water, seem uncontrollable.
The prediction of where materials go in such complex environmental flows "remains a formidable scientific challenge," said Shane Ross, associate professor of biomedical engineering and mechanics at Virginia Tech.
Ross, who received a National Science Foundation (NSF) CAREER award in 2012 to study engineering tools to understand and predict fluid motions, is now the co-principal investigator on a new $2.6 million NSF award that will focus on specific methods for the successful prediction, mitigation, and response to an environmental flow hazard.
"If we had had better prediction methods for the chaotic spread of oil during the Deep Water Horizon disaster, or the passage of the ash cloud from the Eyjafjallajokull volcano through commercial air space, or the trail of radioactive waste from the Fukushima reactor disaster, we would be able to greatly improve emergency response and significantly reduce negative consequences. Preparedness and effective response can save many lives, untold environmental damage, and enormous financial cost," Ross said.
"Many fluid flows have a transport network that may not be obvious. By elucidating this network using mathematical tools we can reveal previously hidden patterns of complex motion in flows," Ross said.
Joining Ross on this new project are his Virginia Tech colleagues David Schmale, associate professor of plant pathology and weed science and one of Popular Science Magazine's Brilliant 10 in 2013, and Craig Woolsey, professor of aerospace and ocean engineering and also a previous recipient of an NSF CAREER award and an Office of Naval Research Young Investigator award.
Leading the multi-institutional effort is Thomas Peacock of the Massachusetts Institute of Technology's Mechanical Engineering Department and director of its environmental dynamics laboratory. Joining MIT and Virginia Tech are investigators from Woods Hole Oceanographic Institution and the University of California at Berkeley.
Ross and Schmale have collaborated before. In earlier NSF funded projects leading to their new study, they used unmanned aerial vehicles to study more than 100 airborne samples of Fusarium, a group of fungi that includes devastating pathogens of plants and animals. "The resulting information led to strong evidence that specific atmospheric structures play a role in determining atmospheric concentrations of pathogens," Ross explained. This work was published online Sept. 9, 2011, in the American Institute of Physics' journal Chaos.
An expository article discussing their joint work uncovering the natural 'highways in the sky', which carry not only pathogens but also natural and anthropogenic contaminants, has recently been published in the journal Annual Review of Phytopathology.
In engineering terms, the atmospheric patterns Ross referred to are called Lagrangian coherent structures, named after the 18th century Italian-French mathematician Joseph Lagrange. He introduced the Lagrangian point of view into the study of fluids.
Ross said the recent fundamental breakthroughs in the four-dimensional specter — the traditional three-dimensional plus time — allows "for transformational progress in tackling these science issues using Lagrangian methods."
The field studies the researchers are planning are simulated hazardous ocean and air scenarios. They will use the New England region of the East Coast in the vicinity of Martha's Vineyard Coastal Observatory and Virginia Tech's Kentland Farms airfield, a Federal Aviation Administration approved unmanned aircraft test site.
During these studies, the researchers will integrate the Lagrangian coherent structures methodology with both in situ and remote observations, adaptive autonomous observing platforms, and other modeling methods.
"When hazardous material is released, accurate predictions of where the material is likely to go can greatly improve emergency responses and significantly reduce negative consequences. Preparedness and an effective response can save many lives, untold environmental damage and enormous financial cost," Ross said.