Geoffrey Andrews (MSAAE '17)

AAE Ph.D student Geoffrey Andrews is the 2018 recipient of the AIAA Foundation’s Abe M. Zarem Award for Distinguished Achievement in Aeronautics.

Andrews received the honor for his paper, “A Hybrid Length Scale Similarity Solution for Swirling Turbulent Jets.” Andrews, who earned his master’s in aerospace engineering from Purdue in 2017, is pursuing a doctorate degree in hypersonic computational fluid dynamics.

Andrews has been invited to present the paper at the 31st Congress of the International Council of the Aeronautical Sciences (ICAS) Sept. 9-14 in Belo Horizonte, Brazil. He will be presented with the Zarem medallion at the AIAA Science and Technology Forum and Exposition Jan. 7-11 in San Diego.

The award annually recognizes students in aeronautics or astronautics who have demonstrated outstanding scholarship in their field.

“I’m still slightly in shock about the whole thing,” says Andrews, who was informed last week he’d won the award. “It’s a huge honor to be nationally recognized and to be given the opportunity to represent the United States on an international stage. It still feels a bit surreal. It amazes me that something that began life as a simple class project here at Purdue has earned this level of recognition.

“I’m truly grateful to be part of a department with such high academic standards and chuffed to bits to be pursuing my doctorate alongside some of the best students and faculty in the world.”

Among that faculty is Greg Blaisdell, a professor of aeronautics and astronautics. Blaisdell will receive a certificate of recognition for his work with Andrews, whose award-winning paper was an extended version of a report for a class project in AAE 626, Turbulence and Turbulence Modeling.

“Geoffrey used an innovative approach to examine the scaling of swirling jets,” Blaisdell says. “It is neat to see students go beyond the material I teach in class. However, it is rare that they are then able to publish their work or win an award. I wish Geoffrey hearty congratulations.”

The paper outlines a mathematical model Andrews developed to describe how a swirling jet of fluid develops as it moves.

Imagine blowing through a straw that is quickly rotating around its long axis. The air that comes out of the end will be moving forward (downstream), but it also will have a rotational motion due to the straw. That’s a “swirling jet.”

As the flow develops, it assumes self-similarity, meaning that the profile will eventually look the same at any point downstream, just stretched somewhat. This means that the jet can be described by a similarity solution, which gives the fundamental shape of the jet's profile. Similarity solutions provide a reference for comparison against experimental and computational data. They give a rough idea of what a flow should look like, to know if things are being measured correctly.

“Swirling jets are useful because of their applications in mixing devices,” Andrews says. “They are a promising way to incorporate fuels and reactants in gas turbine engines and other combustion devices. However, they are also quite complicated to generate and study, so there has not been a great deal of work done to develop a deeper understanding of them. My model is far from comprehensive, but it suggests an alternative way of generating a similarity solution for them, using a combination of axial and swirling length scales to characterize the flow.”

Andrews also is part of NASA’s Pathways Graduate Co-op program at NASA’s Glenn Research Center in Cleveland. At Glenn, he’s a member of the Propulsion Systems Analysis Branch where he’s investigating novel propulsion concepts under the Aeronautics directorate. He’s performing cycle analysis on hypersonic engines using a variety of computational tools.