A Brief History of ME at Caltech

by Christopher E. Brennen

Brief history of ME at Caltech

Like the rest of this special institution we call Caltech, the contributions and accomplishments of the Mechanical Engineering Department and faculty have been twofold. On the one hand our students have gone out into the world to power engineering innovation in industry, in government and especially in the universities of the world. On the other hand our faculty and students have made ground-breaking research contributions to key engineering issues and to new technologies.

Like the rest of Caltech, our students are represented in the faculties of the world in numbers out of all proportion to the number of our graduates. From MIT to Michigan and Princeton, from Georgia Tech to Illinois and Johns Hopkins, our Mechanical Engineering graduates are everywhere - including places as far flung as the National University of Taiwan, the University of Pisa, and the National Autonomous University of Mexico.

But also many of our graduates have risen to key positions in industry - in the aerospace business, in the oil industy, in the semiconductor industry, and more recently in the business of inventing new engineering technologies - indeed the scope of the presentations at the ME Centennial show how broad our contributions have been.

With respect to our research accomplishments, like many other Caltech engineering departments it is fair to say that we got off to a slow start in the early days, when the ``Division of Civil and Mechanical Engineering'' (as it was called at the time) focused on training engineers rather than research. Even then, however, our faculty were much involved with the Metropolitan Water District in the planning of the remarkable Colorado River Aqueduct System. Indeed the Pump Lab - which in its various phases was a very valuable contributor to this basic technology - had its start with that project. Thus it was that faculty like Franklin Thomas, Robert Dougherty, Howell Tyson and Don Clark laid the ground work for the new era of engineering research that was to come during and after the Second World War. Encouraged by von Karman, who had himself only recently arrived at Caltech, Robert Knapp built the world's leading research laboratory for cavitation and high-speed water flows. The Hydrodynamics Laboratory and its associated faculty -- Knapp, Hollander, Plesset, Acosta and Wu -- reeled off a body of fundamental research in this area that dominated the subject for decades and, by extension, led to numerous innovations in naval and other applications. It even makes an appearance in Tom Clancy's ``Hunt for Red October''. Moreover, the early work in cavitation naturally led to research in other multiphase flows. Plesset, Sabersky and Marble, for example, were deeply involved in the multiphase research needed for the analysis of nuclear reactor accident scenarios. Sabersky was perhaps one of the world leaders in identifying the problems and issues associated with granular material flows, an area in which research continues to this day.

Other parallel efforts in internal flows began about the same time. The Pump Lab under Knapp's direction continued to revolutionize knowledge of the internal workings of those ubiquitous machines. Kyropoulos's interest in internal combustion engines initiated a strong interaction with GM. And in the same era, Rannie and Sabersky began the first basic investigations of the internal flows in axial turbomachines - an effort that expanded through the efforts of Rannie and Marble into fundamental research on gas turbines and combustion that provided important steps in the development of the modern gas turbine. Later, Zukoski expanded this combustion research to fires in buildings and contributed significantly to the effort and strategy of fire prevention.

The effort in turbomachine research continued through the last quarter of the 1900s, but with the focus shifted to key research on the unsteady flows and instabilities associated with these devices. This led to the first delineation of the dynamic response of these complex flows and a methodology for the analysis of instabilities such as the Pogo instability endemic to liquid-propelled rockets. In a parallel effort, Culick identified mechanisms of instability in solid rocket motors.

This later emphasis on dynamics of all kinds of mechanical devices and natural processes was a strong component of the ME research during the late 1900s. Caughey contributed a veritable library of key advances in understanding non-linear dynamics and how to view the complex probabilistic components of non-linear vibrations.

About the same time Knowles, Sternberg and Shield were making fundamental contributions to the mathematical theory of elasticity. They initiated a systematic study of material instabilities, and this naturally led to the study of phase-transforming solids and active materials. Concepts introduced by Knowles are now part of the standard language of the mechanics of these materials.

Beginning in the mid 1980's, the ME department underwent another metamorphosis, as large in scope as the post-war transformation. Young faculty were hired who struck out in new research directions and who went on to make seminal contributions in fields such as design, control, medical robotics, computational mechanics, thin films and microdevices. ME faculty also took on substantial administrative and leadership roles during this time, including as EAS Division Chair, Chief Technologist at JPL, Vice-President for Student Affairs, Dean of Students, Chair of the Faculty, and Director of GALCIT, greatly expanding the visibility and influence of ME as a whole within the Institute.

Today, there is no doubt that the strength, scope, and visibility of the ME faculty and its activities are greater than they have ever been. As one measure, Caltech's ME program is ranked third in the nation by US News and World Report despite being an order of magnitude smaller than the competition. Remarkably, all of our eligible faculty have won prestigious young investigator awards. Our research activity encompasses new and exciting areas such as robotics in biomedical and biological contexts, new and exotic materials areas such as chemical vapor deposition, fuel cells, and materials with memory, computational efforts to model the most complex solids and fluids, studies of combustion and detonation, analyses and experiments on fracture in materials and in the earth's surface and on granular flows, strategies to model the dynamics and design of large scale systems.

And what of the future? Though predictions of the future are notoriously difficult, research on the crucial topic of meeting the world's energy needs without destroying the planet in the process will certainly be a major focus. Moreover, it also seems clear that there will be real opportunities in three key areas: mechanical engineering on the micro- and nano-scale, research at the boundaries of biology and engineering, and efforts to design and control large and complex engineering systems. ME must strive to find the unique Caltech contributions to these efforts and the world's needs. How will it all turn out? We don't know, but we expect an exciting ride - stay tuned, and we'll tell you all about it at our bicentennial in 2107.

Last updated 3/26/07.

Christopher E. Brennen