Date July 20, 2023
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Anoop Kiran: Helping to shed new light on the aerodynamics of drone flight

Inside Brown’s Prince Laboratory, the engineering Ph.D. student is delving deeper into his passion for flight and working to solve one of the biggest challenges of drone aerodynamics.

PROVIDENCE, R.I. [Brown University] — Whether it’s how airplanes take off and land or how they cruise in the air even through turbulent conditions, one thing has always been a constant for Anoop Kiran: a love of all things aviation and aerodynamics. And this summer is no different.

Each day, the Brown University Ph.D. student finds himself delving deeper into this passion by performing experiments on a pair of drones he mounts onto a metal fixture, one above the other, to closely analyze what happens when drones fly too close together.

“In this case, the upper drone impinges downwash — which is this downward force — affecting the stability of the lower drone,” said Kiran, who this fall will start his second year at Brown’s School of Engineering as part of the fluids and thermal sciences research group. “The downwash effect causes a catastrophic loss of control and prevents drones from being able to fly close together as a team.”

In recent years, drones have become increasingly popular due to their cost-effectiveness and versatility. Many in the flight community are starting to explore drones as options for search-and-rescue operations, tracking toxic gas plumes or other applications like collecting large-scale data for city traffic patterns or delivering mail and packages. These types of drone deployments face a range of aerodynamic challenges, including drones having to fly in close proximity to each other to perform cooperative tasks.

“In the future, if we would like to fly drones for applications such as search and rescue operations or even product deliveries, they would have to work collectively and in really close proximity to one another for operability,” Kiran said. “But there are disturbances and boundary effects that happen when they fly through the air under realistic conditions, so this topic has to be researched, and appropriate robust controllers have to be developed to sustain challenging flight before deploying them in such adverse conditions.”

This is where Kiran’s work this summer may one day make an impact.

He is leading an effort to pinpoint the exact threshold of when and where the downwash that causes loss of control happens. To do that, he built a structure that holds two drones in place so he can get real-time data on the downwash force the top drone is subjecting the bottom drone when he commands their motor to activate. Kiran can adjust the distance on the traverse as needed to make them further apart or closer together, while the sensors attached to the drones feed the data into the algorithms he coded to analyze the data.

So far, he has spent the summer collecting, distilling and interpreting the data based on different distances between the drones. Kiran designed the custom structure so it’s easy to adjust and taught two undergraduate research assistants — rising Brown sophomores Narek Harutyunyan and Faris Wahbeh— to take the measurements and analyze them.

Once he finds the thresholds and after further modeling of the aerodynamics, Kiran eventually plans to validate those measurements through flight experiments.

That’s when the real fun begins.

“Every time I share information about my project with someone, I get excited by the responsibility of taking this research further,” Kiran said.

Along with determining downwash thresholds, he is also starting to think about efficient flight if the downwash could somehow be repurposed and harvested.

“Ideally, there could be collective flight paths that can take advantage of downwash and perform better as in the case of wingtip vortices among birds flying in a ‘V’ formation,” Kiran said.

Kiran’s work, partially funded by a National Science Foundation Graduate Research Fellowship, began in the spring and marked the next step in work he started as an undergraduate at the University at Buffalo, where he studied aerospace engineering.

“I wanted to be a pilot time a long time ago but decided to pursue engineering because I got really interested in the aerodynamics of flight and the challenges in the field around that,” Kiran said. “I wanted to continue that for graduate school, which is why I decided to attend Brown to work on this project… Every day I learn something new. The entire drone community could find this helpful.”