MAE Colloquium - Spring 2016
The Aerospace Engineering Colloquium (AE 598) is a required course that satisfies the professional development component of the Master of Aerospace Engineering (MAE). MAE students are required to complete nine (9) credits of colloquium participation to satisfy the degree requirements. However, all members of the UW community are welcome to attend and participate.
Topics may include current research and advances in aerospace technology as well as other themes relevant to the professional development of aerospace engineers. To earn credit for this course, students must complete a required set of writing assignments.
Mondays, 4:00 - 5:00 pm
Loew Hall 216
Faculty Coordinator: Prof. Anshu Narang-Siddarth
Drones: Challenges for the Future
- Paul Applewhite
The United States has established a definitive lead in military unmanned systems. However, there are significant changes that are occurring in this industry, both domestically and globally. Emerging companies are taking the lead in this new technology and putting the established juggernauts of the aircraft industry on the defensive. US regulations are also putting domestic companies at a distinct disadvantage for participating in this new industry. This talk will discuss the parallels to the early manned aircraft experience, and discuss some of the future challenges for unmanned systems.
Paul has been involved in aviation for over a third of a century. Soloing at age sixteen, he earned his commercial certificate the day he turned eighteen. He became a flight instructor and had soloed his first student before graduating from high school. He went on to get an aerospace engineering degree from Georgia Tech and later a MBA from Auburn University at Montgomery. He has worked as an engineer for aircraft companies such as McDonnell Douglas, Grumman, Sikorsky, and two suppliers to Boeing. Paul has over 13,000 flight hours in everything from bush planes flying above the Arctic Circle to jet airliners flying into cities such as Chicago, Miami, Los Angeles, and Newark. He represented a pilot’s union on some of the early advisory committees tasked with establishing rules for unmanned aircraft. In 2010, he established Applewhite Aero in order to offer quality training in this emerging industry. His company has had some of the first FAA approvals in this region. A transplant from Mississippi, he has lived in Washington since 1993. He lives with his wife and daughter in West Seattle.
Unsteady Loading in Flow Separation and Reversal
The rotorcraft community has a growing interest in the development of high-speed helicopters, but one barrier to the design of such helicopters is the lack of understanding of the aerodynamic behavior of retreating rotor blades that operate in reverse flow. This work considers two fundamental models of the complex unsteady flow environment encountered by rotor blades in the reverse flow region of a rotor disk: static and oscillating airfoils in reverse flow. Knowledge of the time-averaged and unsteady airloads for both of these models is needed to provide insight for the design of rotor blades with improved aerodynamic performance and mitigation of component fatigue and vibrations during high-speed flight. To this end, two-dimensional wind tunnel tests have been performed on four airfoil sections: two featuring a sharp geometric trailing edge (NACA 0012 and NACA 0024) and two featuring a blunt geometric trailing edge. Time-averaged airloads were measured on static airfoils in reverse flow using a custom-built force balance system. Flow field measurements were captured using time-resolved particle image velocimetry (TR-PIV). Airfoils with a blunt geometric trailing edge were found to delay flow separation to greater angles of attack. This leads to a decrease in drag, but also an increase in downward-acting lift and pitching moment. Three unsteady flow regimes were identified: slender body vortex shedding, turbulent wake, and deep stall vortex shedding. Unsteady airloads were measured in these three regimes using unsteady pressure transducers mounted beneath the airfoil surface. The magnitude of the unsteady airloads has been found to be greatest in the turbulent wake regime; the unsteady airloads in deep stall are moderate in magnitude and periodic due to vortex-induced-vibrations.
Anya Jones is an Assistant Professor in the Department of Aerospace Engineering. She received her PhD in experimental aerodynamics from the University of Cambridge, United Kingdom, her S.M. in aeronautics and astronautics from MIT, and her B.S. in aeronautical and mechanical engineering from Rensselaer Polytechnic Institute. Her research is focused on the experimental fluid dynamics of unsteady, three-dimensional, and separated flows. Her current projects focus on unsteady low Reynolds number aerodynamics, vortex dynamics, flapping wings, and separated and reverse flow rotor aerodynamics. She is currently chair of a NATO Research Technology Organization task group on unsteady aerodynamics and a member of the Alfred Gessow Rotorcraft Center at UMD. She has been awarded the AFOSR Young Investigator Award, NSF CAREER Award, and the PECASE from the White House.
Dynamics of detonations: what controls the burning rate and how to model it?
Detonation waves are supersonic reaction waves. Their application to propulsion applications, such as the Rotating Detonation Engine, requires the control of the wave speed for different boundary conditions. The prediction of the detonation dynamics is currently very difficult, due to the intrinsic multi-scale character of the wave structure. The present talk addresses the dynamics of detonations with geometrical divergence that one would encounter in Rotating Detonation Engines.
The talk will highlight the physics of unstable turbulent detonation waves, and explain how the reaction zone structure details affect the detonation dynamics on larger scales, by controlling the gas-burning rate. A recently demonstrated computational methodology to treat detonation waves is discussed, based on the Linear Eddy Model for turbulent combustion and its extensions to compressible flow in the context of Large Eddy Simulations.
Dr. Matei I. Radulescu is currently Associate Professor in the Mechanical Engineering Department of University of Ottawa, Canada. Dr. Radulescu obtained his Ph.D. in 2003 from McGill University, Canada. Before joining the University of Ottawa in 2006, he was a postdoctoral fellow at Stanford, Princeton, Keio and Leeds Universities.
His research interests are currently focused on gas dynamics in reactive media, as applied to fast combustion and detonation waves in propulsion and safety applications.
Dr. Radulescu was the recipient of the Bernard Lewis Fellowship offered to outstanding young researchers by the Combustion Institute in 2004 and a Visiting Professor at Caltech in 2015.
Dr. Radulescu teaches undergraduate courses in Fluid Mechanics and graduate courses in Combustion and Gas Dynamics.
- P. Wolański, Detonative propulsion, Proceedings of the Combustion Institute 34(1) 125–158 (2013).
- J. E. Shepherd, Detonation in gases, Proceedings of the Combustion Institute, 32(1) 83-98 (2009).
- B. McN. Maxwell, Turbulent Combustion Modelling of Fast-Flames and Detonations Using Compressible LEM-LES, Ph.D. thesis, University of Ottawa 2016. Thesis available from www.ruor.uottawa.ca/handle/10393/34122
Building Your Network
- Ms. Holly Longman
Engineering Career Center, University of Washington
Networking is a great strategy for securing employment. Serious job-seekers take initiative to make themselves known by others who might have job leads, contacts, or advice. Many people, however, are afraid of networking or unsure how to go about it. This presentation defines networking and discusses an array of networking strategies.
Holly Longman is a Career Coach within the Career Center @ Engineering at the University of Washington. Prior to her career at UW, Holly served as the Program Manager for the Women in Engineering Program at Ohio State University. With a background in counseling, Holly enjoys working with students to discover their strengths and their passion.
Sampling-Based Techniques for Planning and Control of Autonomous Spacecraft and Space Robots
- Dr. Marco Pavone
Assistant Professor, Aeronautics & Astronautics, Stanford University
Prof. Pavone will present a novel guidance framework for safely and efficiently maneuvering autonomous aerospace vehicles in dynamic and cluttered environments. The discussion will cover some of the unique aspects of the "spacecraft motion planning problem" including a review of how a sampling-based motion planning algorithm called the Fast Marching Tree algorithm (FMT*) has been adapted for use in spacecraft motion planning. (Tractable inclusion of differential constraints, deterministic convergence guarantees, and planning under uncertainty via Monte Carlo sampling.) The talk will conclude with an overview of related projects in the field of autonomous aerospace systems currently under investigation in his research group. This project is a collaboration among Stanford, NASA Goddard, and NASA JPL.
Dr. Marco Pavone is an Assistant Professor of Aeronautics and Astronautics at Stanford University, where he is the Director of the Autonomous Systems Laboratory. Before joining Stanford, he was a Research Technologist within the Robotics Section at the NASA Jet Propulsion Laboratory. He received a Ph.D. degree in Aeronautics and Astronautics from the Massachusetts Institute of Technology in 2010. His main research interests are in the development of methodologies for the analysis, design, and control of autonomous systems, with an emphasis on autonomous aerospace vehicles and large-scale robotic networks. He is a recipient of an NSF CAREER Award, a NASA Early Career Faculty Award, a Hellman Faculty Scholar Award, and was named NASA NIAC Fellow in 2011. His work has been recognized with best paper nominations or awards at the Field and Service Robotics Conference (2015), at the Robotics: Science and Systems Conference (2014), and at NASA symposia (2015). He is currently serving as an Associate Editor for the IEEE Control Systems Magazine.
Touchless Relative Attitude Control of GEO Objects
Detumbling GEO objects is a critical component of many space debris remediation or satellites servicing missions being envisioned. A touchless method of controlling the relative spin and attitude of the passive space objects is discussed. Here active electrostatic charging is employed via a primary electron gun on the host spacecraft. The electron emission is aimed at the passive space object to charge it negatively, while the servicer is charged positively. This creates milli-Newton level forces if the spacecraft are 3-4 craft radii apart. Recent research has been investigating modulating this electrostatic force field to control the relative spin and orientation without requiring physical contact. The Multi-Sphere-Method (MSM) is being developed to facility faster-than-realtime charged astrodynamics simulations. Terrestrial experimental results are discussed to validate these models, and illustrate the performance of closed-loop 1-D attitude control. Further, early results of studying three-dimensional charged relative attitude motion are presented illustrating how the natural relative motion of spacecraft can be exploited to remove most of the rotational energy.
To be announced...
- To be announced...
Engineering Career Center, University of Washington
To be announced...
To be announced...
Dynamics and Control of Flexible Flight Vehicles: Theoretical, Computational & Experimental Perspectives
- Prof. Ashok Joshi
Department of Aerospace Engineering, Indian Institute of Technology, Powai, Mumbai, India
Evolution of flight vehicles e.g. aircraft, launch vehicles and missiles etc., over the past many decades, has thrown up many innovative systems that aim to achieve very high levels of performance. However, these developments have also made the systems complex in nature, causing increased levels of interactions among the many disciplines that contribute to such high performances. For example, significant reduction in weight, even with use of newer light-weight materials, has invariably come at a cost of a highly flexible airframe leading to undesirable servo-elastic and aero-servo-elastic effects. Similarly, high maneuverability and accuracy requirements have always come with a price of marginally stable or even unstable aerodynamic geometries as well as higher actuator bandwidths and control gains, resulting in greater noise and other control related issues. Further, with advances in mini and micro aerial vehicles, all the applicable disciplines are found to be tightly coupled requiring a multi-disciplinary design approach for synthesizing such systems.
The present talk provides an overview of some of the important issues, coming under the broad area of dynamics and control, which need to be tackled during the design and development of different types of aerospace systems. The issues that are taken up for study in this talk are servo-elastic and aero-servo-elastic interactions, which occur in aircraft and missile systems, and need critical attention. In this regard, a set of case studies, dealing with missiles, launch vehicles and fixed-wing aircraft, are discussed through generic formulations that establish procedures for modelling and analysis of these effects. Focus of these case studies is to bring out the nature of interactions and their impact on the overall system behaviour in the context of a given mission.
The case studies are a mix of analytical, computational and experimental investigations that bring out the practical aspects of dealing with servo-elastic and aero-servo-elastic interactions that are commonly present in most aerospace systems. The vehicles that have been employed in these cases studies are sufficiently realistic so that complex interactions are representative and generic for that class of vehicles. Lastly, the non-dimensional results, though qualitative in nature, still establish the various trends with a sufficient degree of realism.
The talk is expected to sensitize the designers, practitioners and researchers about capturing the servo-elastic and aero-servo-elastic interactions through appropriate models and employing solution methodologies to synthesize systems that are consistent and robust.
None scheduled this week due to Memorial Day.