Lizards and frogs are about to take up residence in the laboratories of Virginia Tech’s College of Engineering.
The engineers want to learn more about the water-running ability of some lizard, which in engineering terms, means how it increases its locomotion efficiency by producing more force on its power stroke and less drag on its recovery stroke.
They will also be studying some frog species can generate enough propulsion to jump out of the water using only one power stroke and catch a flying insect that may be some 40 centimetres – or three times their body length – above the surface.
The National Science Foundation (NSF) is also curious. The US government agency has a Physics of Living program that funds research projects at the interface of biology, mathematical modelling, physics, and engineering and they have awarded more than half a million dollars to investigate the water entry and exit problems in mechanics.
Professor Sunghwan Jung, principal investigator, said: “Since there are no engineered systems that operate under conditions similar to these reptiles and amphibians, we have an opportunity to learn how nature effectively uses the interaction of these forces.
“From our findings we hope to be able to develop bio-inspired systems such as faster dipping and coating processes for materials engineering, or even water-walking robots.”
Researchers will also look at the fluid dynamics of drinking in carnivorous animals, specifically cats and dogs. Two years ago, Prof Jung participated in a study with researchers from MIT and Princeton University that showed a cat’s drinking strategy works to defeat gravity.
A feline will actually pull liquid into its mouth and this ability to exploit fluid inertia to defeat gravity and pull liquid into its mouth has significant implications for the development of novel microfluidic devices.
By contrast, the domestic dog appears to scoop water into its mouth, using its highly curled tongue that penetrates into the water. The amount of fluid ingested depends on the lapping frequency and the size of the air cavity created by the canine’s tongue.
“The animal systems described provide a series of examples in which the hydrodynamics of the water entry or exit enable exceptional and counter-intuitive behaviours,” Prof Jung said. “We selected them based on their apparent similarity of air cavity formations compared to numerous engineering applications operating on water surface.”
Professors Jake Socha and Pavlos Vlachos will also benefit from the funding. Prof Socha leads a large interdisciplinary team that includes engineers and biologists on the study of how insects move fluids through their bodies, including air, blood, and food, whose goal is to derive new engineering principles for fluidic applications.
Prof Vlachos, who is a previous recipient of an NSF CAREER award on arterial flow dynamics, is also a co-principal investigator on an NSF Integrative Graduate Education and Research Traineeship program on multi-scale transport in environmental and physiological systems. Socha also participates in this grant.