© 2019 by David W. Murphy

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The goal of the Murphy Lab is to explore fluid mechanics in the context of biology, ecology, and the environment. Recent interests include the hydrodynamics of animal swimming and sensing and the dispersion of oil spills. 

 

By studying the intersection of life and fluid mechanics, we aim to draw design principles and inspiration to solve human engineering problems.

In our multidisciplinary investigations, we work collaboratively with biologists, ecologists, oceanographers, public health professionals, and medical doctors. 

We often use experimental tools such as high speed imaging, particle image velocimetry, and holography.

Ongoing Projects
Pteropod Swimming Diversity
Pteropods exhibit a diversity of shell shapes and sizes. We are studying the effect of this diversity on swimming ability and fluid dynamics in an effort to find bio-inspiration for underwater vehicle design.
Metachronal Locomotion
In metachronal swimming, appendages are sequentially stroked from the back to the front of the animal. This pattern is widely used and is thought to increase swimming efficiency. We are studying the fluid dynamics of metachronal swimming and how it is used among animals of drastically different sizes.
Collective Animal Behavior
Animals in schools and swarms interact with each other through fluid dynamic signals and may save energy by maintaining certain positions relative to other animals (i.e. 'drafting'). We are using stereophotogrammetry and flow measurements to study the fluid dynamics of collective schooling behavior in Antarctic krill.
Langmuir Cells
Oil droplets and sediment particles may be entrained into the water column by Langmuir turbulence. We are studying oil-sediment interaction in a laboratory model of this flow. Funded by the Gulf of Mexico Research Initiative.
Tiny Insect Flight
The aerodynamics of flight by mm-scale insects is quite different from that of larger insects and bears many similarities to sea butterfly swimming. We are experimentally measuring the flow generated by tiny flying insects using PIV.
Health Effects of Oil Spills
Oily vapors and aerosol droplets released from oil spills are thought to harm the health of nearby animals and humans. We are studying the effect of oily vapor exposure on the cardiovascular system of embryonic Gulf killifish.
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Past Projects
Antarctic Krill Swimming
The Antarctic krill is the keystone species of the Southern Ocean. It swims by beating its five pairs of legs in a back-to-front metachronal stroke pattern. We studied the kinematics and hydrodynamics of the swimming legs and found lift-producing vortices that aid in swimming.
Swimming of the Sea Butterfly
We show that the
zooplanktonic sea butterfly 'flies' underwater in the same way that very small insects fly in the air. Both sea butterflies and flying insects stroke their wings in a
characteristic figure-of-eight pattern to produce lift, and both generate extra lift by peeling their wings apart at the beginning of the power stroke.
Crude Oil Jets in Crossflow
Oil well blowouts such as the Deepwater Horizon disaster create buoyant, immiscible jet and plumes of crude oil jets emanating from the sea floor. The dispersion of this oil is influenced by ocean currents. We studied the impact of current speed and chemical dispersant application on the behavior of these jets in crossflow.
Raindrop Impact on Oil Slicks
The impact of a single large raindrop onto an oil slick floating on the sea surface ejects thousands of microdroplets of oil into the air as aerosol. Dispersion of oil droplets into the atmosphere is a previously unrecognized fate for spilled oil and has unknown implications for public health and air quality. We studied the effect of oil slick thickness and chemical dispersant application on splash characteristics and aerosol droplet production.
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at the University of South Florida
Langmuir Cells

Oil droplets and sediment particles may be entrained into the water column by Langmuir turbulence. We are studying oil-sediment interaction in a laboratory model of this flow. Funded by the Gulf of Mexico Research Initiative.