Melissa Pappas
With a research career dedicated to atmospheric wind and fluid mechanics, Nathan Wei, Assistant Professor in Mechanical Engineering and Applied Mechanics (MEAM), takes his endeavors almost wherever the wind blows. Guided by his desire to make an impact in the realm of energy and sustainability and his commitment to mentoring the next generation of problem solvers, a very intentional wind blew Wei to Penn, where he can do both with creative freedom.
“In academia I can dive into both fundamental and applied science while having the opportunity to teach, mentor and guide today’s students, our future engineers,” says Wei. “At Penn, I can collaborate with and learn from world-class engineers who are already tackling the many pressing challenges in modern society, which are not purely engineering challenges, with an interdisciplinary approach.”
With interests spanning the intersection of unsteady aerodynamics, climate science and wind-energy technologies, as well as their ecological, environmental and societal implications, Wei sees interdisciplinary collaborations as large and long-term goals at Penn. But first, he plans to find his niche, develop his expertise and work with students to begin to approach energy and sustainability problems in a collaborative way.
Wei’s expertise is within wind turbine dynamics and large-scale atmospheric flow measurements with experience gained throughout his research career. Wei’s bachelor’s degree is in Mechanical and Aerospace Engineering, which he earned from Princeton University in 2017. He then spent a year at the Technical University of Darmstadt in Germany as a Fulbright fellow examining how aerodynamic structures, such as wings, sails and propeller blades, respond to unsteady gusts of wind. From there, Wei began working with John Dabiri on the unsteady aerodynamics of wind-energy systems, receiving his master’s in Mechanical Engineering from Stanford University in 2020 and a Ph.D. in Aeronautics from the California Institute of Technology in 2023.
“These ‘unsteady’ flow motions, or gusts of wind, can suddenly change speed and direction in ways that can be quite unpredictable,” says Wei. “These characteristics are not typically captured or considered in the modeling and design of aerodynamic objects, such as airplane wings and wind turbine blades, because they are challenging to model. However, that doesn’t mean they don’t exist.”
On the contrary, Wei believes that these gusts of wind could be leveraged to harvest even more energy from wind turbines or to help light aerial vehicles navigate more efficiently if they were examined, understood and leveraged in the design of these systems.
“If we let what is actually happening in the atmosphere inform our design choices rather than what is easiest for us to model, we can actually get more out of our work,” says Wei. “We’ve already been able to show significant power increases in unsteady turbine systems, particularly for offshore turbines that have an additional unsteady characteristic: the rocking back and forth due to wave energy. The next question is ‘how can we adapt existing turbines to take advantage of these unsteady flows to be even more efficient?’”
Inspired by the sentiment attributed to Einstein, “everything should be made as simple as possible but not simpler,” Wei sees the opportunity to implement these ideas using existing turbine designs to not only enhance the technical and economic potential of the wind-energy industry, but to make wind energy more accessible and affordable for remote and under-resourced regions around the world. These objectives are closely tied to Wei’s interests in the physics of wind itself.
One of Wei’s potential research ideas at Penn is to develop field experiments with incoming graduate students to measure large-scale atmospheric flow using tethered balloons, drones or other airborne platforms to track and model wind movement.
“Working with students in the field teaches them how science and life work,” says Wei. “There is not always a right or wrong answer when you come face to face with unsteady, unpredictable weather patterns that challenge your models and expectations. The chaos and turbulence of the atmosphere is a metaphor for life. You have to adapt to it and build resilience.”
Balloons and drones, affordable alternatives to traditional wind-measurement systems such as meteorological towers and LiDAR, which cost anywhere from thousands to hundreds of thousands of dollars, may provide insights into an area’s wind patterns to help a community determine the best placement and design of a wind turbine to generate the most power. This kind of project aligns with Wei’s commitment to making technology accessible while encouraging engineers to care more about the human impacts of their work.
“By designing accessible technologies, students learn to consider and care for others’ needs,” says Wei. “Our ultimate goal as engineers is to get science out of the ivory tower and empower those in need to expand on our work, add their own innovations and adapt our ideas to their specific situations and problems.”
Another project Wei hopes to get off the ground as new students enter his lab is one investigating how wind turbines interact with atmospheric flows. By setting up particle tracking systems with light or neutrally buoyant particles, such as helium-filled bubbles or artificial snow particles, Wei and collaborators can use cameras to track their pathways and measure atmospheric turbulence.
“While we do a great job of thinking about how we can take advantage of wind, wave and solar energy to meet our needs, we don’t always consider the broader environmental effects of these systems. Tracking how wind turbines interact with atmospheric flows would help us better understand those connections and engineer a renewable-energy sector that operates in harmony with the natural environment.”
These proposed projects will undoubtedly require technical knowledge of these systems, topics that Wei will dive into in his fall semester course on wind energy and the atmosphere, but they will also require an open-minded approach to problem solving that embraces societal, economic and policy connections as well. To accomplish this, Wei is creating a research environment that will welcome students with diverse backgrounds and interests to engage these problems in a more holistic and interdisciplinary way. Wei has understood how asking for help and admitting your limitations are strengths in collaboration, not weaknesses, and encourages students to adopt this mindset.
“I try to approach problems with epistemic humility,” says Wei. “It is important to know that we have limitations in our field and that we as individuals see the world from one, limited perspective. We don’t have to know the answer all of the time, and sometimes not knowing and then asking others for help initiates the best collaborations. I’m excited to not only share this philosophy with my students but to practice it as a teacher and mentor.”
Learn more about Wei’s research and student opportunities by visiting his Aerodynamics Wind And Renewable Energy (AWARE) Lab website.