ECU engineering students have acoustic research published

Two East Carolina University undergraduate students had research published through the Acoustical Society of America.

Faith Cobb and Nia Wilson, both engineering majors, have been working with Dr. Teresa Ryan, associate professor in the Department of Engineering, on sound propagation research as part of a grant through the Office of Naval Research. The goal of the research is to help improve a numerical model of sound in air. That model can ultimately improve the real-time information military commanders have to determine whether someone on shore could hear an approaching craft given wind, temperature, sea state, shore vegetation and other factors. That’s important not only to protect the ship from enemy fire, but also to protect the personnel on board while conducting the mission.

As part of that overall project, Wilson’s work focused on vertical temperature gradient while Cobb looked at the acoustic properties of sand under various moisture levels — both of which affect sound waves.

Nia Wilson

Nia Wilson

A rising senior from Raleigh, Wilson used a drone to measure air temperatures up to 25 meters in height, or about 82 feet. Temperatures can vary by height, and temperature is just one factor that affects sound waves. Wilson’s research found that current temperature assumptions could be flawed based on differences with temperatures closer to the ground. In other words, if the model is incorrect at lower heights, that error could be carried throughout the model to increasing heights.

“The propagation models look completely different from — based on the actual temperature data — what they’re supposed to look like. They’re just not specific enough in modeling that,” Wilson said.

She said she was excited to learn the work had been published.

“I was very honored to have something published like this,” she said. “It’s a big deal for an undergraduate student to have something published, especially one in a well-known group like the Acoustical Society of America.”

Wilson said the work isn’t complete. The focus of the research will look at temperatures up to 100 meters high as well as a more comprehensive look at temperatures from the ground up to 5 meters.

And that means more work with the drone.

“I was actually very hesitant about flying the drone because I was worried about crashing it,” Wilson said. “For the most part, I take over the iPad part of it. I just make sure the drone is flying the pre-programmed flight and hopefully everything goes well. Every once in a while it will bounce off the ground, but for the most part, I don’t want to fly the drone. I’ll let somebody else do it. It’s just too much to think about for me.”

Faith Cobb

Faith Cobb

A rising senior from Lake Waccamaw who is also part of the accelerated master’s program, Cobb’s research focused on how moisture levels in sand could disrupt sound waves.

By taking various sand samples, Cobb determined the transition from wet sand to dry sand on the beach was about 3 meters, or just shy of 10 feet. By testing sand samples with different moisture levels at different depths, the research determined that dry sand absorbs more low frequency sound, but wet sand absorbs more high frequency sound.

“We know by our model how much of the sound is going to be absorbed or affected by the shore,” Cobb said.

Cobb, who has been part of Ryan’s research team since her freshman year, said she was excited to see the research published.

“I didn’t expect it,” she said. “Coming in as a freshman, I didn’t expect to have these opportunities this early in my academic or overall career in engineering.”

Cobb said she’s learned a lot through the research.

“I’ve learned a lot more about engineering and different parts about engineering research and the tools used to accomplish that,” she said. “Honestly, there’s some stuff I’ve learned more from research than I have from taking classes. It’s definitely some fantastic opportunities that have given me a jumpstart on my postgraduate education and my future career.”

What’s next?

The project will continue this summer. While much of the work took place on ECU’s West Research Campus this past fall and spring, the team of students will expand the scope of the research by placing a sound source on a boat in the Croatan Sound just offshore from the Coastal Studies Institute at ECU’s Outer Banks campus in Wanchese.

Though Wilson and Cobb have another year to go before graduation, the research has given them some long-term goals.

“This research has me thinking about aerospace, so I’m thinking of going to get my master’s in aerospace engineering,” Wilson said.

“I would like to obtain my Ph.D. in mechanical engineering and I would like to pursue engineering research, whether that’s for something along the lines of a military lab or for another similar organization,” Cobb said.