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Department: Mechanical and Aerospace Engineering

Dabiri Mechanical and Aerospace Engineering

John O. Dabiri ’01

Assistant Professor of Aeronautics and Bioengineering,
California Institute of Technology

What does a mechanical and aerospace engineer do?

As a freshman at Princeton I knew that I wanted to pursue engineering in general, but I hadn’t seen enough of any particular discipline to pick a specific major. I was leaning toward mechanical and aerospace engineering (MAE), if for no other reason than the title “rocket scientist” had a nice ring to it. Yet I still didn’t have an appreciation of what an MAE major would actually do on a day-to-day basis in a job. Toward the end of my freshman year, Professor Mike Littman gave a presentation about the MAE program that has stuck with me to this day. Although he gave some specific examples of what an MAE might do for a career, he especially impressed on me the fact that we would learn the fundamentals necessary to pursue almost any career path. I suppose the fact that I am currently on the San Juan Islands chasing jellyfish with a laser means that he was right.

One of the most valuable lessons I learned at Princeton was that once you develop a deep understanding of the fundamental concepts in a particular field of study and combine that knowledge with a little creativity, you can impact neighboring fields of study or even create entirely new ones. For me, this meant first learning the basics (and sometimes not-so-basics) of fluid dynamics, the behavior of air, water, and even blood. Among the physical sciences, fluid dynamics is peculiar in that the governing equations have been known since the 19th century, yet to this day we can only solve those equations in very simple cases. I can still remember my skepticism about the usefulness of a subject in which so few exact solutions exist. I found it messy. Yet the faculty in MAE taught us to use our creativity and the ingenuity of our predecessors to take basic physical concepts and design a Boeing 747 or a nuclear submarine. Messy or not, fluid dynamics became my passion.

Jellyfish and jumbo jets

By my senior year, I was so inspired by my interactions with the MAE faculty that I decided I wanted to have the same impact on the next generation of students as they had on me. I decided to pursue graduate studies in the area of biological fluid dynamics at Caltech. My training at Princeton allowed me to make the leap from measuring the drag on an airplane wing to examining similar phenomena in birds. Problems of oil transport in pipelines transformed to blood flow in the cardiovascular system. On the surface, the problems might seem somewhat unrelated. However, the perspective that I gained in the MAE department at Princeton enabled me to take advantage of tools from engineering to better understand biology and, conversely, to extract nature’s design principles in the creation of new engineering technologies.

As a graduate student, I used that perspective to find useful similarities between blood flow in the human heart and the water currents generated by swimming jellyfish. The result was a new diagnostic tool for evaluating early stages of heart failure. Today, I am on the faculty at Caltech, where my interests have further expanded to issues of renewable energy extraction from wind and water, and to the possible role of animal-fluid interactions in global climate change. I have tried to emulate the way that my professors from Princeton encouraged students to think broadly about a field of study: to be less concerned with accumulating knowledge for a future job and more interested in understanding how new knowledge is synthesized in the first place. If you make this the priority as you plan your academic path, your Princeton education will enable you to tackle jellyfish or jumbo jets, whichever you prefer.

“I have tried to emulate the way that my professors from Princeton encouraged students to think broadly about a field of study: to be less concerned with accumulating knowledge for a future job and more interested in understanding how new knowledge is synthesized in the first place.”