Welcome! We do fluid dynamics research at the University of Delaware. Primarily, we design and study systems that sense, respond to, and manipulate an unsteady fluid flow around them. These include flows that are unsteady purposefully (fish swimming) or chaotically (turbulence). Our research leads to better vehicle design, robots with new methods of propulsion, or novel ways to save energy.
Fish and other aquatic animals are remarkably proficient at swimming fast and efficiently. We study their swimming techniques to better understand unsteady propulsion. With this knowledge we can design more effective propulsors than current propeller technology. The initial part of this work was funded by the Office of Naval Research and conducted at Princeton University.
PRF (2017): Non-sinusoidal gaits
PRF (2017): Trailing edge shape impact
JFM (2017): Scaling laws of swimming
AMS (2017): Intermittent swimming
PRF (2018): Swimming speed
AIAA (2018): Performance of fish-like swimming
PNAS (2018): Drag dictates swimming/flying efficiency
Coherent structures in turbulence
Wall-bounded turbulent flow is complex and chaotic - however, there is an organization within the chaos. Turbulent flow often has coherent and predictable flow structures. Wall-bounded turbulent flow comprises hairpin vortices that can conglomerate into large scale motions which contain a majority of the flow's energy. We study ways to possibly target specific coherent structures and mitigate or excite them. With this knowledge, we will be able to better describe and control the energy-containing motions in turbulent flows, which has the potential to influence many practical aerodynamic and hydrodynamic flows. The initial part of this work was funded by the Office of Naval Research and conducted at Princeton University.
TSFP 10 (2017): Turbulent pipe flow response to mode targetting
TSFP 10 (2017): Self-similar structures in turbulent pipe flow
Unsteady and steady jets
Synthetic jets are generated from rapid blowing and suction of air through an orifice. This creates a train of vortex rings, which results in a time-averaged jet. Synthetic and steady jets have both been widely studied as flow control devices for application, but there is a significant gap in the fundamental understanding of these flows. Using devices like these, we can develop systems that sense and respond to a changing surrounding flow field. This work was initially funded by the Boeing Company and conducted at RPI.
PoF (2016): Synthetic jet in a crossflow
PoF (2016): Impact of orientation on synthetic jet in crossflow
Exp. Therm. Fluid Sci. (2016): Steady jet synthetic jet comparison
J. Aero. Eng. (2016): High speed and momentum synthetic jet
PoF (2015): Synthetic jet vortex generator interaction
J. Vib. Acoust. (2015): Synthetic jet cavity acoustics
JFM (2014): Synthetic jet vortex formation
PoF (2014): High Reynolds number synthetic jets
Turbulence-induced blood damage
Red blood cells are vital for transporting oxygen throughout our circulatory system. Turbulent flow can produce stress-inducing eddies on the order of the same size of blood cells, causing hemolysis. Luckily, turbulence is not something that often occurs within our bodies. Unfortunately, turbulence can occur in blood being drawn through a needle, leading to a wasted sample; or it can occur in dialysis machines, causing life-threatening damaged blood to be put back into the body. We study the interaction of turbulence with blood cells and develop devices which would provide doctors with the ability to cheaply and quickly assess blood damage as it happens. This work was originally funded by the Helen Shipley Hunt fund at Princeton University.
Alternatives for wind energy harvesting
The rising demand for clean energy has led to some creative advancements in wind energy collection strategies. Helmholtz resonance occurs when air in a cavity is perturbed by oscillations, most commonly experienced when blowing over an empty soda bottle. We propose a device for generating power from the wind that couples a piezoelectric element to a Helmholtz resonator. These resonators could be used as an alternative energy source for small and large scale power needs, to power remote sensors, provide the energy needs of a single house, or augment local energy needs in urban environments. This work was originally funded by the Princeton E-ffiliates in partnership with The Southern Company.