N. Agastya Balantrapu, who will graduate in December with a Ph.D. in aerospace engineering, has been challenged by his research of aerodynamics and aeroacoustics. In his five years at Virginia Tech, he has performed complex experimental research on the structural behavior of boundary layer turbulence. He has collaborated with government agencies and researchers at both domestic and international universities, and formed meaningful relationships with faculty mentors while also serving as a mentor to others.

More importantly during his time here, Balantrapu has received a platform to achieve his fundamental goal: to educate future generations of engineers.

Balantrapu hails from Hyderabad, India, and had initially considered pursuing a degree in computer science. As an undergraduate, he enrolled at Jawaharlal Nehru Technological University Hyderabad in Telangana, India.

In India, the aerospace industry is not a research-based industry, but rather is focused on the design and manufacturing of aircraft. At the suggestion of his father, Balantrapu explored a few courses in aeronautical engineering. After meeting a professor, Dr. Kunal Ghosh, whose work focused on fluid dynamics and wind energy, Balantrapu became interested in exploring the field further and ultimately earned a bachelor of science degree in aeronautical engineering in 2014.

Inspired by his undergraduate mentor and armed with a goal to teach others, he set out to earn his doctoral degree. Balantrapu took a six-month break to learn new languages, and then began applying to graduate programs at a number of universities. He was accepted to Virginia Tech and arrived in Blacksburg in the fall of 2015.

Admittedly struggling a bit, specifically with his aero/hydrodynamics course, he joined professor William Devenport’s research group within the Center for Renewable Energy and Aero/Hydrodynamic Technology (CREATe). During the past four years, he has become an integral part of the team and a mentor to undergraduate students and students pursuing their master’s degrees.

“Since his first introduction to the research team, Agastya has transformed himself into an outstanding researcher and leader,” said Devenport. “He sees well beyond the many technical details and challenges of the specific research and has a real understanding of the larger purpose of the research. This drive has led to some truly impactful discoveries, as well as an appreciation of the educational and societal benefits of the research. He has taken on leadership roles in CREATe as well as in undergraduate teaching, and thus has prepared himself well for an outstanding career in academia or industry.” 

At the Center for Renewable Energy and Aero/Hydrodynamic Technology, Balantrapu’s work has been highly experimental in nature, measuring the structure of turbulent boundary layers ingested by a rotor.

Simply explained, he is working to make quieter vehicles for air and sea. Propulsion systems in marine vehicles, submarines and aircraft all have rotors that generate thrust. In many cases, turbulence gets drawn into the rotor and is a big contributor to the noise. The turbulence comes from the surface of the vehicle where friction causes the formation of eddies — small whirlpools of flow coming off the surface. With better understanding of how such complex turbulence behaves and interacts with rotors, engineers have a better grasp of the effects it has on the efficiency of air flow, and how to reduce noise.

This fundamental research has relevant applications to the U.S. Navy and the Office of Naval Research, as there is interest in improving the low acoustic signatures in submarines in terms of stealth or reducing noise in short haul air transportation.

Under Devenport, Balantrapu had the opportunity to design and lead five commercial-scale wind tunnel campaigns in Virginia Tech’s Stability Wind Tunnel for the Office of Naval Research. The project, which measured the structure of a body-of-revolution flow and its ingestion by a rotor, required coordination of inter-university collaborators and managing fellow doctoral candidates, masters students and undergraduates throughout the campaign.

Graduate students work in the Aeroacoustics Lab
Balantrapu (right) and a fellow graduate student measure the characteristics of the flow on the plate using a hotwire anemometer in Virginia Tech’s Wall-Jet facility in May 2017. Steve Edwards for Virginia Tech.

He also designed and conducted experiments in the Wall-Jet Facility, documenting the dynamic response of pinhole microphones under grazing flow; and collaborated with Denmark Technological University in the implementation of a novel “finlet” technology, designed to reduce trailing edge noise on a Nordtank 500 kW wind turbine.

While performing scientific research is gratifying, Balantrapu has not wavered from his long-term goal. “According to Dr. Devenport, you can contribute only so much through your research, but through teaching you have a profound impact, an impact you cannot imagine,” said Balantrapu. “It has always been my goal to teach. Last semester I was vested the full power of handling the fluid mechanics class for undergraduates, and through that experience is when I knew for sure I wanted to become a teacher.

“That is what Virginia Tech has given me. Teaching has always been my goal, and Virginia Tech has provided me with an excellent platform to achieve it. Dr. Devenport has been a fantastic mentor and I could not have asked for more in the past five years.”

In addition to serving as a graduate teaching assistant for courses including compressible aerodynamics, computational methods, and experimental methods, among others, Balantrapu has also been an active mentor for fellow students. He has advised a number of graduate and undergraduate students in designing and responsibly conducting experiments and on how to critically analyze data. He takes immense care in advising them and finds great pride in their successes.

Throughout his time at Virginia Tech, Balantrapu has held various leadership positions and participated in a number of student organizations. He served for four years on the Dean’s Graduate Team and for one year as the chair of the Torgersen Research Awards for the College of Engineering. He also served as a panelist for the Virginia Tech Graduate Honor Systems and as a member of the Title IX Student Advisory Board. Balantrapu is a student member of the American Institute of Aeronautics and Astronautics, and founder of the CREATe Student Association, a professional association to improve the research culture within the Center for Renewable Energy and Aero/Hydrodynamic Technology.

Balantrapu was named the Outstanding Graduate Student for the Kevin T. Crofton Department of Aerospace and Ocean Engineering in 2020, and is a recipient of the John L. Pratt Fellowship, and the Eleanor Davenport Fellowship.

As commencement approaches, Balantrapu is a bit disappointed that this important milestone has been marred by the COVID-19 pandemic. Long ago, he imagined his parents present for the commencement ceremony, and walking across the stage in Cassell Coliseum to be hooded by his faculty advisor. He hopes to return to campus once it is safe to hold in-person ceremonies again.

Looking on the bright side, he is grateful to be at this stage of his degree in 2020. “Most of my colleagues are not so lucky and have been more adversely affected with their classes being held online,” said Balantrapu. “I was fortunate to have taken all my classes in person prior to the pandemic.”  

Balantrapu is currently looking for post-doctoral research positions across the United States and hopes to begin looking for a teaching position in the next five years.

“I am grateful to Virginia Tech for truly transforming me into a better researcher, teacher and person,” he said. “Ever closer to my goal, I am eager to take on new scientific challenges to make our community a better place, while preparing a future generation of engineers to do the same. This is my promise of Ut Prosim!”

Written by Jama Green

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