Award Data

The occurrence of combustion instability has long been a matter of serious concern in the development of liquid-propellant rocket engines due to the high rate of energy release in a confined volume in which energy losses are relatively small. Shear layer instabilities and intermittent growth rates of the mixing layer cause fluctuations in the burning rates and result in acoustic waves triggering ...

Combustion stability is an important consideration in the design of liquid rocket engines. While fundamental modes of unstable operation in simple geometries are easily identified using analytical methods, recent times have seen these methods greatly expand in scope, applied in semi-numerical format to increasingly complex geometries and flow situations. Much remains to be explored in understandin ...

Quantitative predictions of reactive flow dynamics from large-scale simulations of Liquid Rocket Engines (LRE) appear to be model dependent. Relationships and coupling among the dominant mechanisms most responsible for destabilization are obscured by the complexities of the model and subtle consequences of inherent ad hoc approximations not supported by mathematical rationale. The reliability of ...

The ever-decreasing size of the electronic microchips and the ever-increasing density of electronic components required to support future Air Force platforms are creating the problem of substantial localized heat generation that can impair component operation. State of the art thermal interface materials (TIMs), that are used to dissipate heat from the source to the spreader in a microchip, are se ...

Carbon-carbon (C-C) composites are used in the fabrication of aeroshells and thermal protection systems (TPS) in hypersonic and atmospheric reentry applications because they maintain their strength at elevated temperatures and have desirable thermal conductivity properties. Although these materials have been used in mission-critical components for decades, the effects of variations in processing m ...

ABSTRACT: In this project, we assemble leading commercial and academic groups within nano-scale device simulation community to overcome the modeling bottleneck by implementing new high performance modeling methods for simulating the electrical properties of nano-scale devices. The majority of the tools will be integrated into an already existing and very user friendly commercial platform for simu ...

Metamaterials and photonic crystals are engineered composites that exhibit novel and interesting properties not found using ordinary materials. They have been shown to allow extraordinary control over the electromagnetic field, including molding the flow of energy, amplitude profile of the field, phase of the waves, intermodal coupling, and more. To achieve such control, a set of tools and procedu ...

Current scene projection hardware is challenged to simultaneously meet the requirements for high peak temperature (> 2000K), high resolution (> 1Kx1K), response time < 1 ms, cryogenic and temporally uniform photon flux. MEMS, Resistor arrays, liquid crystals, and photonic crystals all suffer in one or more areas. MEMS suffer from flicker and low dynamic range. Resistor arrays suffer from low frame ...

We apply the theory of partially observable Markov decision processes (POMDPs) to the design of guidance algorithms for controlling the motion of unmanned aerial vehicles (UAVs) with on-board sensors for tracking multiple ground targets. While POMDPs are intractable to optimize exactly, principled approximation methods can be devised based on Bellman’s principle. We introduce a new approximation ...

We propose to develop ultradense plasmonic integrated devices and circuits for optical interconnect compatible with the electronic circuitry. In our proposal, we will employ engineered metallic nanostructures that combine energy concentration by plasmonic lenses and retardation-based plasmonic resonances to even further boost the efficiency of materials exhibiting optical nonlinearity. These plas ...