Christopher Douglas: Shaping the Flow of Fluid Dynamics

Christopher Douglas will join the faculty of Duke Engineering as an assistant professor in the Thomas Lord Mechanical Engineering and Materials Science Department, beginning in January 2025. Bringing deep academic and research knowledge, Douglas plans to establish a leading research group focused on thermo-fluid dynamics, with an emphasis on renewable energy and sustainability.

His research interests took shape as an undergraduate, but graduate school is where his pursuits took off. He obtained a PhD from Georgia Tech in mechanical engineering, studying the thermo-fluid dynamics of gas turbine combustors like those found in airplanes and power plants. His work has since evolved to focus on a range of fundamental topics in fluid and flame mechanics, as well as more applied research contributing to the decarbonization of other transportation and energy systems.

One of Douglas’ specific areas of expertise is in alternative fuels, particularly hydrogen. In a recent conversation, he explained some of the complexities of using it to replace conventional fuels.

“We are now in a race to create energy systems that release as little CO₂ as possible without sacrificing safety or cost,” he said. “And one promising way to do that is to switch from burning fossil-derived fuels like natural gas or conventional jet fuel to potentially renewable fuels like hydrogen. But hydrogen, the smallest molecule, is a really tricky fuel to control.”

“If you have a tiny, light molecule, it diffuses very rapidly,” Douglas explained. “And because it diffuses faster than other molecules in a combustor (like oxygen), hydrogen flames often exhibit a behavior called thermo-diffusive instability.”

In practical terms, this instability means that instead of maintaining smooth, conical flames like those found on top of a Bunsen burner in a chemistry lab, hydrogen flames tend to wrinkle into intricate shapes. These wrinkles increase the flame’s surface area, which, in turn, accelerates the combustion process significantly. “And so, there’s this really beautiful and complex interplay between a microscopic property of the hydrogen molecule and its macroscopic behavior as a fuel,” Douglas said. 

“My PhD supervisor and postdoctoral supervisors have also deeply inspired and challenged me, shaping how I ask and answer questions and approach new problems, but it was my mom who taught me curiosity and persistence.”

He points out that because of these interactions, switching fuels often isn’t as simple as swapping one for the other. The entire combustion system may need to be re-engineered to accommodate hydrogen’s rapid burning rate, and its tendency to form these complex, wrinkled flame structures. This challenge of stabilizing the flame within the combustor, especially when dealing with varying flow rates, is a critical aspect of engineering combustion systems for alternative fuels.

Douglas credits his scientific enthusiasm to two particular mentors from his undergraduate studies who piqued his interest in an academic career through microelectromechanical systems research, and later introduced him to the field of thermo-fluid dynamics through a capstone project. 

“My PhD supervisor and postdoctoral supervisors have also deeply inspired and challenged me, shaping how I ask and answer questions and approach new problems,” he shared. “But it was my mom who taught me curiosity and persistence.”

Douglas’s move to North Carolina brings him closer to family in Virginia, Tennessee, and Florida. An avid hiker, rock climber, runner, and cyclist, he is also eager to explore the nature surrounding Duke’s campus. “I miss the southern warmth,” he further shared. “Not just in the weather, but in the people – even strangers you meet on a walk or at the grocery store.”

At Duke, Douglas is excited to collaborate with high-achieving students and other faculty members on complementary interests. “Duke has a long tradition of excellence in fluid mechanics and nonlinear sciences,” he said, citing examples like Earl Dowell, William Holland Hall Distinguished Professor of Mechanical Engineering and Materials Science, and Kenneth Hall, Julian Francis Abele Distinguished Professor of Mechanical Engineering and Materials Science. 

Douglas additionally aims to participate in Duke University initiatives like campus-wide grants on climate change and to engage with centers like the Nicholas Institute for Energy, Environment & Sustainability and the Center for Nonlinear and Complex Systems.