ARNOLD AIR FORCE BASE, Tenn. -- For more than 30 years, Marvin Sellers has led the charge in advocating and advancing the pressure-sensitive paint capability in the Arnold Engineering Development Complex wind tunnels at Arnold Air Force Base.
His work has not gone unrewarded.
Sellers was recently named the winner of the 2024 American Institute of Aeronautics and Astronautics Ground Testing Award.
“I was very excited,” said of his reaction to the award. “It was very unexpected to get that recognition.”
This award, and other annual AIAA technical and management honors, were presented during the AIAA AVIATION Forum, held July 29 to Aug. 2 in Las Vegas, Nevada. Sellers attended the conference to collect the certificate and medal that came with the recognition.
“I saw lots of interesting papers and got to interact with a lot of people,” he said. “It was weird, people you don’t know recognize you from the awards and they’re like, ‘Oh, congratulations.’ It’s a strange feeling to be recognized by people I don’t know.”
According to its website, AIAA is the world’s largest technical society dedicated to the global aerospace profession. It was created in 1963 and, today, has approximately 30,000 individual members from more than 90 countries, as well as 95 corporate members.
The AIAA Ground Testing Award is presented for outstanding achievement in the development or effective utilization of technology, procedures, facilities or modeling techniques for flight simulation, space simulation, propulsion testing, aerodynamic testing or other ground testing associated with aeronautics and astronautics.
His award citation reads that Sellers was recognized for “decades of tremendous contributions to the national ground test and evaluation community, most particularly in the advancement of pressure-sensitive paint techniques.”
Sellers said he learned from the AIAA that he would be receiving the award more than a month before the forum. He was nominated for the honor by a member of the AIAA Ground Testing Technical Committee which, according to the AIAA, focuses on matters related to the testing of vehicles, structures and aerospace systems, subsystems and components in ground-based facilities such as wind tunnels, environmental facilities and engine test facilities.
“One of the people on the committee that I know, he had nominated me for that award knowing the work that I had done not only in PSP but also in other things that I’ve worked on here at AEDC in my career,” Sellers said.
Sellers said he has not only received his fair share of congratulatory remarks from his peers at Arnold, but he has also garnered kudos from others he interacts with regularly, such as fellow members of his church. Sellers was unaware the award winners had been announced in the Tullahoma News, so he was pleasantly caught off guard by these proverbial pats on the back.
“It’s pretty fun having people get excited for you,” he said.
Sellers has earned other individual honors during career at Arnold. In 2013, he was inducted as an AEDC Fellow for “demonstrating developmental excellence in many technical areas” such as PSP test techniques, wind tunnel model design, data acquisition and processing, and instrumentation and flight systems business development.
The AEDC Fellows program, established in 1989, recognizes AEDC personnel who have made substantial and exceptionally distinguished contributions to the nation’s aerospace ground testing capability.
While he referred to his Fellows induction as the “highest accolade” he’s ever achieved, Sellers said winning the AIAA award compares quite favorably.
“That was real exciting to get that,” Sellers said of his Fellows induction. “This is about like getting the Fellows award, except it’s being recognized from other people and facilities around the country and world. So that’s a pretty neat award.”
Sellers has spearheaded the development of PSP techniques at Arnold AFB since 1991. While he neither developed the paint itself nor the PSP capability, Sellers is credited as the primary person responsible for bringing it to AEDC wind tunnels.
In general, the PSP technique relies upon a special paint and illumination source combined with sensitive cameras to obtain surface pressure data. The paint is applied to a test article in two layers – a white undercoat and the PSP layer. The undercoat provides a uniform reflective surface for the PSP layer.
The illumination source excites the PSP layer, which fluoresces with intensity inversely proportional to the surface pressure on the test model. Intensity variations are captured with digital black and white cameras, and two images are acquired – one with the wind in the tunnel off and with the wind on. The ratio represents the pressure distribution.
From there, image processing is performed to convert the intensity ratio to pressure and combine images from multiple cameras onto a three-dimensional grid that the represents the model. The pressure values are correlated to different colors on this grid for easier visualization of the pressure variation on the model surface.
Sellers said he has received a great deal of help with his PSP efforts over the years, from the programmers who helped developed the code that allowed him to process collected data to those who helped install the related systems on test carts and ensured that they worked.
“I don’t want to take all the credit,” Sellers said. “I had a lot of people that helped me along the way. I’ve just been leading the effort and pushing for it.”
Sellers mentioned two colleagues in particular who have contributed significantly to his work with PSP. The first is the now-retired Dr. Wim Ruyten.
“He and I worked like a team, essentially,” Sellers said. “He was the math behind the effort that I was trying to develop.”
The second is current AEDC employee Zachary Lowry. Sellers said Lowry has helped him evolve the PSP capability by ensuring that optical systems operate congruently with those used in data processing.
Sellers graduated from the University of Tennessee in Knoxville in 1981 and came to work at Arnold straight out of college. He said he is grateful for the experiences he has amassed throughout his 43-year career.
“When I was going through aerospace engineering at UT, I thought I wanted to be involved in wind tunnel testing, and so I was real excited when I found out just down the road from me is the largest ground test facility in the world, and I was lucky enough to be able to come to work here and have enjoyed every minute of it,” he said. “Wind tunnel testing is a lot of fun. You see a lot of different things. For me, it’s exciting to develop new capabilities, new technologies.
“I’ve just been thankful for being able to have this opportunity. That’s been a real blessing to have this opportunity to work here and to get to do the things that I’ve been doing. The reason that I’m working still is that I really enjoy my work, and I hope that I can keep contributing to help the younger folks that are coming up behind me and instill in them the same type of things that were instilled in me when I came to work here and pass it on.”