United States of America
From Leadership Profile: Vertiflite July/August 2018
Dr. Anya Jones, Associate Professor, University of Maryland
Within the Department of Aerospace Engineering at the University of Maryland, Anya Jones teaches advanced fluid dynamics and unsteady aerodynamics to graduate students and conducts an undergraduate course in incompressible aerodynamics. In parallel, she researches wing-gust encounters and chairs a NATO research group on the topic. “Gusts are both really interesting and really complicated, in part because they can be of any strength and any direction,” Professor Jones observed. “Think about a helicopter hovering in the air-wake of a ship. There’s flow coming from all sorts of directions at all sorts of time and length scales. What’s most important here? And how can we figure out how this affects the airloads on the blades [or] wings?”
Jones did her doctoral research and much of her subsequent work on rotating wings, specifically those at high angles of attack where leading edge flow separates and forms strong vortices. She has published extensively on rotor wakes, rotor blades in reverse flow, and other topics relevant to rotary-wing flight. Jones conceded, “I knew nothing about helicopters before I joined the University of Maryland. I can thank [Prof.] Inder Chopra and the rest of my UMD colleagues for introducing me to the field.” She added, “It’s hard to work much rotary-wing material into my undergrad class. It’s a very full schedule with all of the basic fluid dynamics and wing theory that we need to cover, but I do squeeze in an introductory lecture towards the end of the semester and it’s always a favorite. We have more time in the grad-level unsteady aero class, so there we cover a fair bit of rotary-wing material including dynamic stall and some flow modeling techniques.”
Jones earned her bachelor’s degree in aeronautical and mechanical engineering from Rensselaer Polytechnic Institute in 2004, a master’s degree in aeronautics and astronautics from the Massachusetts Institute of Technology (MIT) in 2006 and a doctorate in experimental aerodynamics from the University of Cambridge in 2010. She said, “When I first started college, I wanted to work for NASA or possibly in industry. I hadn’t really thought about an academic career, but one of my professors mentioned it early on, and the idea stuck. I never really thought twice about it after that. I did do several internships in industry and government labs throughout undergrad, just to be sure, but academia is definitely what I love.”
Jones grew up in New Orleans, Louisiana, without family ties to engineering or aerospace. “My father was a police officer and my mother worked in a bookstore. I can’t remember a time when I didn’t like aerospace, mostly space as a kid. I wanted to be an astronaut.” Jones attended the prestigious Benjamin Franklin High School on the campus of the University of New Orleans. She recalled, “I had some good science teachers over the years, and I always liked science in school. I got more interested in the air side of things as a junior in high school when I did a science project on Stokes flow.
“Honestly, I chose the project because it seemed simple — all I had to do was make shapes out of clay and drop them down a graduated cylinder of fluid. In previous years I’d always chosen biology-related projects. It turns out that math is harder in fluid dynamics, but that was it; I was hooked.” Jones added, “I’m pretty sure I’ve never heard someone say that they know too much math. There’s so much to cover in today’s engineering curriculum that it’s easy to pass by, but it never hurts to be comfortable with math.”
After high school, Rensselaer offered an aerospace program and put the future engineer/teacher on an academic career path. “I had a great undergraduate advisor at RPI who taught me how to apply to graduate school and fellowship programs. In the end, I went to MIT because it seemed like a place where I’d have room to change and grow. I knew I wanted to do research in aerodynamics, but as an undergrad applying to graduate schools, I didn’t know exactly what that meant. MIT seemed like the kind of place where I’d be exposed to a lot of new things and be able to find interesting opportunities.
“I didn’t end up doing aerodynamics at MIT, but rather multidisciplinary design optimization on an interesting program — the Silent Aircraft Initiative. This was a large joint program between MIT and the University of Cambridge. I really enjoyed my visits to Cambridge in the UK, and I met faculty there doing the experimental aerodynamics that I was particularly interested in, so I decided to make the change, move across the ocean, and really focus on experimental aero. When I accepted the offer at Cambridge, I thought I’d be doing work on supersonic boundary layers, but when I arrived, my project switched to low-speed flows and rotating wings. The rest is history.”
Jones’ current research combines real-world experiments and computer modeling. She and other University of Maryland researchers last year demonstrated, for the first time, time-resolved flow field measurements of reverse flow using particle image velocimetry (PIV) in the school’s Glenn L. Martin wind tunnel. “In my work, I take a lot of data in wind tunnels and/or water tanks/tunnels. We’ve had a lot of advances in hardware and experimental techniques over the last 10 years or so, and now we can take more data faster than ever before. Perhaps, as a result, one challenge that we’re facing is what to do with this data. Having more and more of it doesn’t do us much good if we don’t know how to analyze it and reduce it to something we can comprehend. For sure, there’s good work in this regard, and certainly new analysis techniques all the time. I think we need to start paying attention to those — and perhaps learn new tricks from other communities — and bring them to maturity.”
Jones’ wing-gust research focuses on large-amplitude gust encounters where the magnitude of flow unsteadiness grows large enough to violate the small disturbance assumption in classical aerodynamic theories and where wing response is nonlinear. “It’s a hard problem for a lot of reasons,” explained Jones. “A big one being that there isn’t even an accepted definition of what a ‘gust’ is, and we don’t know which gusts will be important. There aren’t a lot of precise measurements of wind gusts, even though we intuitively know that they’re very common. We need new ways of modeling/predicting these interactions, but before we even get there, we need to figure out what the most important characteristics of these gusts are.” On unsteady flow modeling, Jones observed, “It seems that a lot of our understanding of rotor aerodynamics comes from experiments or numerical simulation, and modeling for design is generally data-driven. I see a lot of value in building models that include first principles as well as data. They may not always be the quickest way to a new design, and they may not always be the most accurate predictors, but they really help us to understand the physics of these complicated flows. Once we understand the underlying physics, we can start thinking bigger and more out-of-the-box to really make leaps forward in technology. Those may be new flow controls, actuators, flight controls, or configurations. We won’t have to make incremental changes to existing designs, but really think things through from the ground up.”
Modern computer tools still need work, according to Jones. “Well, I’m biased, but I would take a step back and look at the fundamental flow physics. I think that’s where we’ll get the new ideas for radical changes in technology in the future. Right now, my motivation for this is in gust/ disturbance rejection because I think we can’t contend with really large disturbances without fundamentally changing how we think about them. You can’t tickle a fully separated flow with a tiny actuator and expect it to do much. You have to do something bigger. But what? We’re not sure yet.”
Jones continued, “Coupled with my interest in disturbance rejection is my interest in rotorcraft autonomy and control. All of the aerodynamics know-how in the world won’t get us far if we can’t translate this understanding into models that can be used for flow or flight control. I’m very interested in how controller programs are written, how they use flow models, and what kind of information they need and how fast they need it. How well and how fast can you estimate/ predict a flow through optimal sensor placement?”
Jones joined AHS International, The Vertical Flight Society, in 2010. “I heard about it from my colleagues when I joined UMD,” she recalled. “AHS provides a venue to get to know colleagues across the rotorcraft field from many institutions. This has given me the chance to build some great collaborations that would have been difficult to form otherwise.”