Physics equations drive optimization of complex engineered systems
Computational models allow researchers to analyze and design complex systems, but development can be a slow process. Leifur Leifsson, associate professor and principal investigator of the Computational Design Lab, uses physics equations to optimize engineered systems for aircraft and space systems as well as microwave systems, nondestructive testing systems and food-water-energy systems.
“I’ve always loved mathematics,” Leifsson says. “Taking the mathematical model and converting it into computer code can be really challenging, but I enjoy that challenge. Once you have that implementation, you can use it to analyze really complex systems and understand how they behave.”
Leifsson first became interested in advancing fundamental computational methods for surrogate-based modeling and optimization while working on his master’s thesis in his home country of Iceland. His research focused on a company that was developing autonomous underwater vehicles.
“I was fascinated by how I could model the fluid flow of the ocean water around the vehicle,” Leifsson says. “The same principles apply to modeling propulsion systems. I began reading about computational modeling in aerospace and decided to pursue a PhD in aerospace engineering.”
After earning his PhD from Virginia Tech, Leifsson worked in industry at two startups and Airbus UK before joining the faculty at Reykjavik University. Prior to coming to Purdue in 2021, he was an associate professor of aerospace engineering at Iowa State University.
“One of the first conferences I presented at, Bill Crossley chaired that session,” Leifsson says. “I was really nervous but Bill was so helpful and supportive and so I always remembered Purdue and Bill Crossley. Purdue is a highly collaborative environment. The opportunity to engage in cross-disciplinary research with other faculty and teach students at one of the best engineering schools in the country was very exciting.
“My research is very collaborative in nature because I’m modeling systems that involve various disciplines. My role is to integrate the effects of these different disciplines which allows me to collaborate with a variety of people, such as one person who focuses on structures and another who focuses on aerodynamics.”
With the integrated data, Leifsson can create surrogate models, which are simplified approximations of more complex models. The same methods and techniques used to model an aircraft can be applied to food-water-energy systems. One such project involves an analysis of the nitrogen loads in the Mississippi River basin resulting from high yield agriculture in Iowa. The surplus nitrogen is carried to the Gulf of Mexico, resulting in the generation of a hypoxic zone — an area of low oxygen that can kill fish and marine life near the bottom of the sea — that has a detrimental impact on the environment.
“Much of the nitrogen in the soil comes from the application of fertilizer,” Leifsson says. “The water flowing through the state creates an interconnected system. By modeling the plants, energy and flow of water, we can predict how different levels of nitrogen used in Iowa will affect the Gulf of Mexico depending on situational variables such as weather.”
Using data to predict outcomes satisfies Leifsson’s constant drive for curiosity, a trait he strives to inspire in his students.
“Each student is different and has different interests,” he says. “I try to inspire curiosity and encourage them to derive questions because if I’m just telling them what to do, they won’t be as engaged. Students need to learn to be autonomous in conducting their own research. It will make them stronger researchers and better engineers in the future.”
This story appeared in the Fall 2022 issue of Purdue University’s Aerogram magazine.
