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Some of the material in is restricted to members of the community. By logging in, you may be able to gain additional access to certain collections or items. If you have questions about access or logging in, please use the form on the Contact Page.
As demand for more efficient and higher-performing aerospace platforms increases there is a need to address challenges that have been left unsolved through a more comprehensive understanding of the complex flowfields and the underlying...
In this dissertation, disturbances leading to optimal energy growth in a spatially developing, zero-pressure-gradient turbulent boundary layer are examined. The slow development of the turbulent mean flow in the streamwise direction is...
Mechanical and Electrical Characterization of Critical Current Density in Round and Rectangular Reinforced BiโSrโCaCu2Oโโโ Wires for High Field Magnet Applications
In recent years there has been a large push for magnet technologies extending into the 20 to 30 T range. High field solenoids can be made using resistive materials like Cu, however the resistive losses associated with Cu electromagnets...
Shockwave boundary layer interactions (SBLI) occur on both internal and external surfaces and adversely affect both the structural and propulsive performance of high-speed flight vehicles operating in the trans/super/hypersonic flow...
The air intake captures the freestream airflow and delivers it to the engine of the parent vehicle for thrust production. The shockwave boundary layer interactions (SBLI) in the intake duct play an important role in defining the flow...
Oxygen free high conductivity (OFHC) copper was processed using equal channel angular extrusion (ECAE), drawing, swaging, or ECAE plus either drawing or swaging to a strain of 4. All processing was carried out at room temperature. The...
A device that can be used to attenuate noise generated in an engine nacelle of an aircraft is an acoustic liner. A conventional single degree of freedom (SDOF) acoustic liner is comprised of a perforated face sheet, honeycomb cells, and...
Active flow control can achieve substantial performance gains and meet the challenges of next-generation air vehicles and energy harvesting devices. The use of active flow control techniques with the deflecting flap or morphing surfaces...
At high angles of attack, asymmetric vortices are formed on the leeward side of flight vehicles with pointed forebodies due to the random surface imperfections near the forebody apex. These vortices induce adverse side forces and yaw...
Wingtip vortices develop at the tips of aircraft wings due to a pressure imbalance during the process of generating lift. These vortices significantly increase the total aerodynamic drag of an aircraft at high-lift flight conditions such...
Autonomous robots are increasingly working alongside humans in a variety of environments. While simple applications in controlled environments work fine with fully autonomous robots and little interaction between human and robot, mission...
Unsteady fluid flows have complex dynamics due to the nonlinear interactions amongst vortical elements. In this thesis, a network-theoretic framework is developed to describe vortical and modal (coherent structure) interactions in...
Superfluid helium (He II) contained in porous media is examined. In particular, heat transfer experiments were performed on He II contained in random packs of uniform size polyethylene spheres. Measured results include the steady state...
Autonomous ground vehicles (AGVs) are commonly used for search and rescue, military and forestry purposes. To safely and efficiently perform missions in these environments the AGV must adapt its driving and control strategies based on...
This study aims to examine the use of a fundamental thermal input for separation control and provide a design guideline via resolvent analysis. The use of the thermal actuator is motivated by the interest in the use of thermal-energy...
Nanoscale ion diffusion is an important phenomenon governing the energy conversion efficiency, stability, degradation pathway, and lifetime of both soft and condensed engineering materials. Block copolyelectrolytes are one of the leading...
The superfluid phase of helium-4, known as He~II, is predominantly used to cool low-temperature devices. It transfers heat by a unique thermally driven counterflow of its two constituents, a classical normal fluid and an inviscid...
The ability to traverse over unknown, rough terrain is an advantage that legged locomotion has over wheeled systems. However, due to the complexity of multi-legged systems, researchers in legged robotics have not been able to reproduce...
In this document, we develop and demonstrate a framework for simulating the mechanics of polymer materials that are reinforced by carbon nanotubes. Our model utilizes peridynamic theory to describe the mechanical response of the polymer...
During their 473 million-year diversification, gnathostomes came to exploit an unprecedented variety of trophic niches. Modifications to dental form and mineralized tissue constituents (i.e. enamel, dentines and in a few taxa, cementum)...
Legged animals have long been shown to excel at maneuvering and navigating the complex and changing environments found in the natural world through a combination of highly actuated musculoskeletal structures, robust and flexible control...
This work develops protocols to obtain a well-dispersed ฮฒ-amyloid(1-40) nanofiber network, as well as methods to integrate the nanofiber network with microfabricated metalized electrodes. To investigate conditions needed for the...
The National Aeronautics and Space Agency (NASA) is working toward going back to the moon and beyond. Currently they are developing a dewar that can store liquid hydrogen (LH2) and liquid oxygen (LO2) in space so the capsule may refuel...
An increasing number of applications require the use of high temperature superconductors (HTS) such as (RE=Rare Earth) Ba2Cu3O7-x (REBCO) coated conductors [1]. HTS conductors show particularly great potential for high field magnets...
Enhancing the beam energy of particle accelerators like the Large Hadron Collider (LHC), at CERN, can increase our probability of finding new fundamental particles of matter beyond those predicted by the standard model. Such discoveries...
This doctoral dissertation pertains to the study of heat transfer, fluid-structure-thermal interactions, buoyancy-driven flows, and the numerical modeling techniques needed to systematically study the different problems related to these...
Research efforts in shock wave/boundary-layer interactions (SBLI) are motivated by the pursuit of faster, lighter, and more maneuverable aircraft. Flow separation, strong pressure fluctuations, and high aerodynamic heating are all...
Materials for some industrial applications require that the processing do not result in recrystallization. Current method for inhibiting recrystallization involves the use of fine precipitates to pin the grain boundaries from migration....
Legged locomotion is advantageous on difficult natural terrains due to it only requiring discrete ground contacts. Biological systems with limbs have developed multiple levels of control to afford such fast and robust legged locomotion....
Unsteady actuators with a high amplitude output and tunable frequency are needed for the effective and efficient control of many sub and supersonic flows. The development, design, characterization, modeling and implementation of a novel...
With an increase in the number of space transport applications, the need for larger, more powerful and efficient rocket motors are the need of the day. Thus, optimizing the thrust generated by these rocket motors is of great importance, ...
Vortex dynamics of wakes generated by rectangular aspect-ratio 2 and 4 and two-dimensional pitching flat plates in free stream are examined with direct numerical simulation and water tunnel experiments. Evolution of wake vortices...
A short takeoff and vertical landing aircraft in hover creates a highly unsteady flowfield dominated by resonance. The supersonic impinging jet created by this aircraft causes damage to the aircraft and nearby structures, lift loss, hot...
This thesis focuses on the simulation and experimental studies of finned graphite foam extended surfaces to test their heat transfer characteristics and potential applications in condensers. Different fin designs were developed to...
Active flow control (AFC) has the potential for substantial performance gains and meeting the challenges of next-generation high-lift aircraft. High-lift wings employ multi-element trailing edge flaps during takeoff and landing. When the...
Through limb structure and neuromuscular control, animals have demonstrated the ability to navigate obstacles and uneven terrain using a variety of different mechanisms and behaviors. Learning from the capabilities of animals, it is...
Localized and site-specific bottom-up synthesis techniques for one-dimensional nanostructures provide a solution to current challenges in nanostructure placement, integration and system-level manufacturing. This work extends localized...
An earlier work on reactant delivery in a Proton Exchange Membrane Fuel Cell using supersonic microjet impingement showed enhanced distribution of reactant and active cooling effect during operation. By comparative analysis with a...
Currently, few scansorial robots exist that are capable of operating on rough exterior surfaces. None of these platforms have, as of yet, been able to achieve high speed dynamic climbing on these surfaces. This thesis shows that through...
There is a continuing need for improved rigid foam insulation, particularly for cryogenic storage aboard aerospace vehicles. The present work is a material characterization of spray-on foam insulation used on the Space Shuttle External...
Lightweight composite actuators with large bending displacement and high blocking force have great potentials for various engineering applications. Carbon nanotube thin film or Buckypaper-based composite actuators (BCAs) have been...
Several animals build structures to shield themselves from external threats. In some species, however, the function of these constructions goes way beyond that of a simple physical barrier. The odd-shaped mounds created by soil termites...
Biological systems show a reliance upon their capability to adapt limb stiffness as a means to achieve dynamically similar locomotion over a wide range of terrains. The versatility of robotic platforms falls short in comparison to their...
There has been growing use of microscale flowfields in a diverse range of applications, including active flow control. While these actuators have proven effective, further investigation would increase the understanding of these...
The need for increased efficiency and performance of high-speed aircraft has led to the need for a reduction in aircraft weight. One option is to use thinner and lightweight skin panels at different regions of the aircraft, such as the...
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