Junior studies insect flight dynamics

In a culture dominated by graduate level research, undergraduate Tiras Lin has been making a name for himself at Hopkins. Lin, who is currently a junior, began doing research his freshman year with Rajat Mittal of Mechanical Engineering. “Essentially,” Lin said, “the motivation for our research is to start to understand what we can learn from the dynamics of insect flight.”

The long-range goal of this thrust is in the design of Micro-Aerial Vehicles (MAVs). MAVs are small, autonomous or remotely controlled vehicles that can be used where people could not otherwise go. “These can be used for missions such as search and rescue or reconnaissance,” Lin said. Unfortuantely, as of now these vehicles are lacking in maneuverability.

To this end, Lin worked extensively with the Painted Lady Butterfly, which can be used to improve MAVs. “In a lot of previously published research, the mass of the wings has been ignored in the analysis of the rotational dynamics,” Lin said. “The wings of the butterfly are very light; it’s like picking up nothing.”

Despite the seemingly negligible mass, the movement of the wings makes their mass significant. As it flies, a butterfly moves its wings relative to its body at a high rate. This changes the butterfly’s moment of inertia enough to affect its flight dynamics. “For example, a diver will modulate [his or her] body, maybe stick the arms or legs out, to try to rotate slower,” Lin explained.

Lin photographs the butterflies in an artificial habitat at high speeds, and uses computer correlation software to map the movement of every part of the insect’s body over time. By knowing the mass of each body part ahead of time, Lin can calculate the moment of inertia and examine the butterfly’s flight dynamics.

Lin was careful to emphasize the nature of Hopkins’ role in this research area. While the basic science of the flight dynamics is fundamental to the ability to design these MAVs, Hopkins is not currently involved with the actual designing of these vehicles.

As this research is coming to a close, Lin is already moving on to a new project. “[I am] trying to figure out how fruit flies land upside down on a ceiling,” Lin said. This project can again be applied to MAV development, specifically landing dynamics.

“This has presented multiple challenges for the photography side of it,” Lin explained, “since we have to record at high speeds, and because of the small size of the flies, it is very difficult to capture these landing maneuvers up-close on camera.”

Eventually, a Computational Fluid Dynamics (CFD) model of fruit fly’s flight will be created. However, more experimental work must be done before that point. “Does [the fruit fly] use its wings to flip itself around? Does it use its momentum? That’s kind of unclear from the literature,” Lin said.

Lin plans to attend graduate school to study fluid mechanics after he graduates from Hopkins. In addition to write-ups in reputable publications, such as The Huffington Post, The New York Times, and Popular Science, Lin has presented his work at two conferences of the American Institute of Aeronautics and Astronautics, as well as an annual meeting of the American Physical Society’s Division of Fluid Dynamics.

“Conducting the research is one thing, but to gather your results in a presentation and explain them in a way that everyone can easily understand is a whole other beast!” Lin joked.