Significant research has been done on boundary layer flows for large vehicles under constant wind conditions, and on boundary layer flows for very small vehicles during unsteady maneuvers. But there is a lack of research on boundary layer flows for large vehicles under unsteady conditions. Understanding these flows can help to predict and control vehicles that are big enough to carry people as they execute rapid maneuvers or move through urban environments.
Theresa Saxton-Fox recently received a CAREER award from the National Science Foundation to advance scientific understanding in accelerating boundary layer studies.
“We will consider accelerations and decelerations in space, as one would expect for a flow moving over a curved surface, and accelerations and decelerations in time, as one would expect for a vehicle executing a maneuver or operating in gusty conditions,” said Saxton-Fox, an assistant professor in the Department of Aerospace Engineering at the University of Illinois Urbana-Champaign.
Saxton-Fox said others have studied accelerating turbulent boundary layers, especially as they accelerate past a curving shape but have been limited to a single shape, or with only a few constant rates of acceleration.
“We’ll take a different approach, leveraging modern measurement technologies and novel experiments to systematically study how changing a key parameter affects the turbulent response,” she said.
Previously, Saxton-Fox’s research group conducted research examining 22 different static pressure gradients, all similar but with varying maximum strength. They identified a qualitative change in behavior for strong but not weak pressure gradients in which an internal layer, a new boundary layer, formed within the original boundary layer. The threshold for the formation of the internal layer had never previously been observed.
“In this new work funded by the NSF, we’ll apply this systematic variation of parameters to multiple types of accelerating boundary layers to identify how rapidly a system has to change for the physics to be affected, and how it affects the turbulence,” she said.
To be considered for an NSF CAREER award, there must be an educational component, serving a specific population and be related to the researcher’s work. Saxton-Fox’s education project will create a new program called Cascade of Math.
Since 2020, Saxton-Fox has volunteered at the Danville Correctional Center as a part of the Education Justice Project, tutoring incarcerated students in math. Her concept is to identify incarcerated students who are strong in math to teach incarcerated students who are weaker in math.
“Many incarcerated people are ineligible for the high school equivalency courses to get their GED because they don’t have enough background in math,” Saxton-Fox said. “This tiered teaching program helps both those who are already strong in math build new skills while bringing up the levels of those who are weaker, making them potentially eligible to take higher-level courses toward a GED.”
In 2021, Saxton-Fox received an award from the National Science Foundation for her work entitled “Uncovering the self-sustaining cycle in the outer region of turbulent boundary layers.” That same year, she was one of just 38 recipients of an Office of Naval Research Young Investigator Program award.