January 16, 2014
An Ancient Swimming Lizard: Engineers Study Plesiosaur Mobility
April Flowers for redOrbit.com - Your Universe Online
Just add water to two engineers and a dinosaur curator and what do you get? At the University of Alberta, you get the answer to how a giant ancient sea creature swam. The lure of engineering combined with dinosaurs is what attracted fourth-year Faculty of Engineering student Laurel Richards to the project.
Donald Henderson, curator of dinosaurs at the Royal Tyrell Museum started the ball rolling by contacting civil engineering professor Mark Loewen, whose research focuses on water and ice. Henderson emailed Loewen asking for help understanding how the plesiosaur -- an ancient lizard that lived more than 66 million years ago -- could swim stably underwater. Loewen was immediately intrigued.
“He sent me this email and I got back to him right away,” Loewen told Cairney. “I said ‘Yeah—let’s do this!’”
Henderson supplied the engineers with a one-tenth scale model of the plesiosaur—which is actually a lizard, not a dinosaur. The idea was to test Henderson's theory that the lizard needed a fin on the end of its tail to remain stable while swimming.
”The stability of a swimming creature is an extremely complicated problem to solve,” said Loewen. “As a first step, we decided to conduct an experiment to determine if the rigid model remained in a stable position, facing upstream, when submerged in a turbulent flow.”
Richards conducted sophisticated experiments, such as mounting the plesiosaur model so that it could be submerged in an open channel flume in the Department of Civil and Environmental Engineering’s Hydraulics Lab. Essentially, the flume is an underwater version of a wind tunnel that exposes models to water flow instead of air flow.
Richard's tests revealed that the model plesiosaur was not stable when submerged in a turbulent flow. She believes more investigation is required -- a larger model or more sensitive load cell might be used in future investigations to obtain accurate measurements of the destabilizing forces acting on the model. Such tests could then be compared to measurements made with models having tail fins, Richards said.