Assistant professor brings aerospace skills to MechSE

MechSE assistant professor Kelly Stephani is unique among MechSE faculty—she has a bachelor’s degree, master’s degree, and PhD in aerospace engineering. Her research is in computational simulations of non-equilibrium flows, and studies of gas-surface and plasma-surface interactions.

"The fluids groups in both aerospace and mechanical engineering are very interconnected," Stephani said. "My research interests lie in the modeling of fundamental processes involved in gas-surface and plasma-surface interactions, and a lot of the applications within mechanical engineering and many other engineering disciplines require the ability to develop high-fidelity models for solving those kinds of problems. Coming into the mechanical engineering department allows me to work with experts in plasma processing and plasma-material interactions, and my background really sets the stage for establishing collaborations in those areas. That’s what I’m really hoping to accomplish here as a faculty member in MechSE."

Stephani’s work with computational simulation of flow began with her undergraduate and graduate research. After the Columbia disaster in 2002, boundary layer flight experiments were taking place to try to improve detection of damage to the thermal protection system. Stephani’s work was focused on understanding the heating taking place due to roughness in the material, an issue relevant to the causes of the Columbia disaster.

"This was a really fascinating study, because real roughness was introduced into the thermal protection system tiles. The team was able to obtain measurements of the roughness-induced heating to the tiles in situ, so we had really great thermal IR imagery as well as heat transfer measurements deduced from thermocouple data that was taken during the reentry," Stephani said. "We had a great collaboration there. That just hooked me. And ever since then I’ve been really interested in developing high fidelity models and simulation capabilities for these kinds of problems."

Stephani has always been working with particle-based kinetic methods, and she uses them in her research of non-equilibrium flows. Non-equilibrium flows occur against a moving vehicle (such as a space shuttle) when the mean collision distance between particles in the flow approaches a fundamental length scale in the flow, such as the length of the space shuttle. If the mean distance between collisions is large, the likelihood of the particles colliding is very low, and they won’t be able to collide in time to relax the system to an equilibrium state; so the system is non-equilibrium, constantly adjusting until it reaches its final state. This is relevant for upper-atmosphere travel, where the air is thin.

Stephani says her approach to teaching is more or less traditional, but she does put a strong emphasis on one specific aspect of education: introducing relevant and recent research-related topics that are of interest to the material she is teaching.

"I try to introduce as much of the recent research as possible, and that serves two purposes," Stephani said. "The first is that the students get to see how these very fundamental ideas and concepts that we’re learning in class are related to relevant problems in research. But it also allows me to engage them in research that I’m interested in pursuing. And that could serve as a possible stepping stone to bringing students from the classes into my research group."

For Stephani, MechSE was a very natural choice. The computational resources present at the University of Illinois at Urbana-Champaign—Blue Waters, the National Center for Supercomputing Applications—are crucial to her research. Not only that, but MechSE has a reputation for excellence.

"The mechanical engineering department is one of the best in the nation," Stephani said. "There are a lot of great people to work with here, and the academic environment here is incredibly open and collaborative. Having the ability to interface with these individuals is really important, because it allows us to ask bigger questions and tackle the grand challenges facing society including energy sources, design of new materials, and improved performance of engineering systems in extreme environments. The students in the MechSE program are also some of the best in the nation. So setting up a research group here is going to be a very successful experience given the outstanding faculty and resources that we have to work with."

Stephani’s group is called SPARKlab, an acronym for Simulations of Plasmas and Associated Reactive Surface Kinetics. She is always looking for students who are interested in contributing to the group.