New lab fueled by passion for efficient aircraft and automobiles
At the intersection of efficient air and ground transportation is a thermo-fluid phenomenon known as drag resistance. On small objects the force is relatively minimal, but on large objects with a changing path, such as aircraft and cars, the resistance considerably impacts performance.
By making fundamental advances in the understanding and control of drag resistance, Lian Duan, associate professor and Honda Endowed Chair in Transportation in the Department of Mechanical and Aerospace Engineering, is realizing significant improvements in the operation of flight and road vehicles.
Duan is the principal investigator of the Computational Aerodynamics and Flow Physics Lab (CAFPLab), the newest laboratory located at The Ohio State University Aerospace Research Center. His lab focuses on advanced modeling and simulation of fluid dynamics in order to improve vehicle efficiency.
“Both the flow around a high-speed flight and the flow over a road vehicle involve complex, highly unsteady turbulent flows,” he said. “In my lab, we develop and utilize various computer programs, referred to as computational fluid dynamics (CFD), to predict and control the complicated turbulent flow as well as the flow-induced noise and vibration.”
Duan is enthusiastic about the real-world benefits resulting from his team’s research. “Our prediction and understanding of the flow physics will ultimately contribute to the development and efficient operation of flight and motor vehicles.”
Improving hypersonic flight vehicles
Duan is currently applying his research to hypersonic flight vehicles—aircraft moving faster than the speed of sound.
His team has performed groundbreaking work to contribute impactful advances in the field of flow physics, the study of the movement of air or fluid around objects. Specifically, Duan’s lab has used highly detailed computational models – called direct numerical simulations – to learn more about why hypersonic aircraft are impacted by the unpredictable air flows directly surrounding them. They have also discovered key factors affecting how these air flows initially transition from being laminar (smooth) to turbulent (irregular).
These research topics are formally known as turbulence physics and non-equilibrium effects in hypersonic turbulent boundary layers. Results from studies in these areas can be used to design more efficient vehicles.
According to Britannica, up to 50% of an aircraft’s fuel can be used to overcome the thin layer of turbulent air directly surrounding it. Eliminating this drag resistance would result in significant improvements in aircraft efficiency and fuel savings. Eventually, the positive environmental impacts resulting from the reduced fuel consumption could be far-reaching.
“Boundary layer transition and wall-bounded turbulence remain two of the most important unsolved problems not just in fluid mechanics, but in all of classical physics,” Duan shared.
“Our ability to predict the aerodynamic lift, drag, surface heating, propulsion and maneuverability of high-speed vehicles is crucially dependent on the knowledge of transition and turbulence at high Mach numbers.”
Duan’s hypersonic research is being supported by multiple government agencies, including the National Science Foundation, Office of Naval Research and Sandia National Laboratories.
Speeding ahead with motor vehicles
Although just-launched at the Aerospace Research Center, Duan has been developing his dual interests in aerospace and automotive vehicle research for several years. He started his lab at Missouri University of Science and Technology and was recruited to Ohio State in 2019.
Duan was attracted to the university due to the opportunities for interdisciplinary work and a variety of premiere internal and external facilities relevant to automotive research as well as aircraft. One such resource is the nearby Transportation Research Center Inc. (TRC), the largest independent proving grounds and vehicle testing organization in the Americas.
Here, Duan carries out automotive vehicle research.
“Transportation Research Center hosts a world-class multifunctional, full-scale wind tunnel facility capable of aerodynamic and aeroacoustics research activities, spanning from advanced research, through scale-model and full-vehicle development, to production vehicle performance assurance,” he described.
“[My lab works] closely with experimentalists at Honda to conduct experiments/CFD correlation as well as to cross-validate experimental and CFD results.”
The collaboration among Ohio State, Honda and TRC comprises much of Duan’s current research activities. Motivated to better society through efficient and safe travel, both by land and by air, he has high aspirations for future collaborative projects at TRC and beyond.
Prospective graduate and advanced undergraduate students interested in conducting research in areas of hypersonic and vehicle aerodynamics should send their resume and a statement of interest to firstname.lastname@example.org.
by Holly Henley, communications specialist