Each year, the Daniel Guggenheim School of Aerospace Engineering graduates between 30 and 40 doctoral students - each with unique contributions to make in research, academia, industry, and the evolution of the discipline itself. On this page, we provide links to their abstracts and their published dissertations. We're also introducing Next Gen Ideas, a video series in which our doctoral candidates will have ~ 3 minutes to explain research that took them years to produce. (No one ever said aerospace engineering was easy.) Click on the video above to get started.
2019 - 2020 Doctoral Dissertations
Benjamin León: “Enabling Technologies for Autonomous Landing with Robotic Landing Gear” (Advisor: Claudio Di Leo)
Throughout their history, rotorcraft have proven to be an invaluable tool for accessing landscapes that traditional fixed wing aircraft are unable to reach. Pilots or autonomous flight systems often face the complexity of landing on uneven, rugged, or moving ship decks in order to complete their mission(s).
One of the greatest challenges preventing use of advanced controllers in aerospace is developing methods to verify, validate, and certify them with high assurance. Traditional test and simulation-based approaches evaluate system behavior at design time in a subset of the total state space.
Edwin Goh: “Reduced-Order Model for Prediction of Staged-Combustor NOx Emissions with Detailed Chemistry and Finite-Rate Mixing” (Advisor: Professor Jerry Seitzman)
The ground power industry is targeting combined cycle plant efficiencies of 65% and above, which can be achieved primarily through higher combustor firing temperatures. Because conventional combustors fail to meet NOx regulations at such temperatures, there is a pressing need for high-temperature, low-emissions combustors.
Metin Firat Ozcan: “A Methodology for Sampling with a Classifier in Gas Turbine State Pace to Create Transient Surrogate Models” (Advisor: Prof. Dimitri Mavris)
Georgios Boutselis: “Optimization-Based Methods for Deterministic and Stochastic Control: Algorithmic Development, Analysis and Applications on Mechanical Systems & Fields” (Advisor: Prof. Evangelos Theodorou)
Developing efficient control algorithms for practical scenarios remains a key challenge for the scientific community. Towards this goal, optimal control theory has been widely employed over the past decades, with applications both in simulated and real environments. Unfortunately, standard model-based approaches become highly ineffective when modeling accuracy degrades. read the abstract (pdf)
Julian Brew: “Using Sample-based Continuation Techniques to Efficiently Compute Subspace Reachable Sets and Pareto-Surfaces” (Advisor: Prof. E. Glenn Lightsey)
For a given continuous-time dynamical system with control input constraints and prescribed state boundary conditions, one can compute the reachable set at a specified time horizon. Forward reachable sets contain all states that can be reached using a feasible control policy at the specified time horizon. read the dissertation
Kazuhide Okamoto: “Optimal Covariance Steering: Theory and It’s Application to Autonomous Driving” (Advisor: Prof.Panagiotis Tsiotras)
Optimal control under uncertainty has been one of the central research topics in the control community for decades. While a number of theories have been developed to control a single state from an initial state to a target state, in some situations, it is preferable to simultaneously compute control commands for multiple states that start from an initial distribution and converge to a target distribution. read the dissertation
Bradley A. Ochs: “Ignition, Topology, and Growth of Turbulent Premixed Flames in Supersonic Flows” (Advisor: Prof. Suresh Menon)
Supersonic combustion ramjets (scramjets) are currently the most efficient combustor technology for air breathing hypersonic flight, however, lack of fundamental understanding and numerous engineering challenges hinder regular deployment of these devices. This work addresses scramjet-relevant knowledge gaps in the areas of ignition, numerical modeling, and flame-compressibility interaction. read the dissertation
Michael D. Bozeman Jr.: “A Reduced-Order Modeling Methodology for the Multidisciplinary Design and Analysis of Boundary Layer Ingestion Configurations” (Advisor: Prof. Dimitri Mavris)
In response to the increasingly stringent requirements for subsonic transport aircraft, NASA has established aggressive goals for the noise, emissions, and fuel burn of the next generations of aircraft. This has led to the investigation of a variety of unconventional configurations and new technologies. read the dissertation
Kisun Song: “An Architecture Model of the U.S. Air Transportation Network” (Advisor: Prof. Dimitri N. Mavris)
Etienne Bouchard: “Dynamic Assessment of Multiple Aircraft Tethered to a Shared Payload” (Advisor: Prof. Dimitri N. Mavris)
This thesis reports methane (CH4) and a syngas mixture (H2/CO=95:5) autoignition delay measurements relevant to operating conditions of supercritical carbon dioxide (sCO2) power cycle (100 to 300 bar) combustors. To acquire data at these conditions as part of this thesis, a new high-pressure shock tube is designed, fabricated and commissioned. The experiments are conducted for diluted carbon dioxide environments at 100 and 200 bar and at temperatures within the range of approximately 1100–1400 K. read the dissertation
Matthew D. Sirignano: "Experimental Investigation of Nitrogen Oxide Production in Premixed Reacting Jets in a Vitiated Crossflow" (Advisor: Prof. Tim Lieuwen)
The presented work describes the experimental investigation of nitrogen oxide (NOx) emissions from reacting jets in a vitiated crossflow (RJICF). It is motivated by interest in axial staging of combustion as an approach to reduce undesirable NOx emissions from gas turbine combustors operating at high flame temperatures (>1900K). read the dissertation