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Many airplane passengers grit their teeth, white-knuckle their armrests and say a silent prayer for their flight to go smoothly. They know that any sudden disturbance in airflow can cause turbulence — and in turn, a severe case of anxiety.

But in smaller aircraft, such as unmanned aerial vehicles or micro air vehicles, turbulence is more than a bumpy ride. It can severely affect the stability of these vehicles and cause them to lose control. On the other hand, nature’s natural fliers — birds — know how to retain control during airflow disturbances.

Assistant Professor of Aerospace Engineering Samik Bhattacharya is studying the morphing power of bird wings in turbulence through a three-year, $441,000 grant from the U.S. Air Force Office of Scientific Research. The goal is to uncover the secrets of bird stability and engineer a comparable solution for UAVs and MAVs.

“Birds have perfected the art of unsteady flow control through millions of years of evolution,” Bhattacharya says. “They don’t use any separate flaps or slats; rather, they morph their wings and use their feathers to achieve similar feats. However, we don’t know how to utilize similar morphing capabilities in man-made flight vehicles.”

To study these morphing capabilities, Bhattacharya and his team of researchers in the Experimental Fluid Mechanics Lab have 3D printed a set of wings made of black agilus plastic. This material is very flexible, so the 3D model can be morphed along the wingspan to mimic the collapsible structure of real bird wings.

The team will test the wings’ morphing capabilities in high turbulence through a state-of-the-art gust generator system that will be funded by the AFOSR grant. This system will be integrated with the towing tank that’s already operating in the EFML lab. The wings will be placed in the tank with a sensor that can measure the lift and drag forces. Images of the flow field will also be captured with the aid of high-speed cameras.

Along with the gust generator, the AFOSR grant will also fund the hiring of graduate students to work on this project. Bhattacharya says he’s grateful for the award, which is highly competitive.

“It feels great to receive this award from AFOSR, especially because the program that funded this work is one of the few federal programs that support this type of fundamental fluid mechanics research,” he says. “It’s very challenging to receive funding from this program.”

Bhattacharya joined UCF’s College of Engineering and Computer Science as an assistant professor in 2016. He received his doctoral degree in aerospace engineering from The Ohio State University, his master’s degree in aerospace engineering from Auburn University and his bachelor’s degree in mechanical engineering from the National Institute of Technology in Warangal, India. He is also a researcher with UCF’s Center for Advanced Turbine and Energy Research.