L. Gary Leal

L. Gary Leal

University of California at Santa Barbara

1943 – Present

Chemical Engineer
Awarded Bingham Medal 2000
Fellow, Elected 2015

Gary was born in Bellingham, Washington on March 18, 1943. He received his B.S. in Chemical Engineering from the University of Washington in 1965. From there, he obtained an M.S. (1968) and Ph.D. (1969) in Chemical Engineering at Stanford University with Andreas Acrivos (1994 winner of the Bingham medal) serving as his Ph.D. thesis advisor. After graduation, he went to Cambridge University for post-doctoral research as a National Science Foundation Fellow. He then joined the faculty at Caltech, beginning as an Assistant Professor of Chemical Engineering in 1970, moving into an Associate Professor position in 1975, becoming a Professor in 1978, and, finally, being named the Chevron Distinguished Professor in Chemical Engineering in 1986. He also spent time as a Senior Visitor in Applied Mathematics at Cambridge University from 1976 to 1979 and as a Visiting Professor at MIT in 1985/86. Leal left Caltech in 1989 to become Professor of Chemical Engineering and Head of Department at the University of California, Santa Barbara, serving as Chair until 1998 and then again from 2004 to 2008. The pre-eminence of that department as one of the Centers of Chemical Engineering on an international scale is a testimonial to Leal’s leadership and vision. Leal was made the Warren and Katharine Schlinger Professor of Chemical Engineering in 2003.

Gary's research contributions to rheology cover a wide spectrum of subjects and are characterized by a blend of analysis, computations and sophisticated experiments. For example, his research on drop deformation and breakup has led to key results and fundamental insights that have become classic contributions to the field. His experiments using a computer-controlled four roll mill produced the most complete set of measurements on this problem and may never be matched in thoroughness and precision. His group’s results on the dynamics of droplets have laid the foundations for much of the present work on the rheology of blends and emulsions. Furthermore, Gary developed a general theory for describing the dynamics of orientable particles and the migration of particles in weakly-elastic matrix fluids which have become the basis for subsequent constitutive theories for a wide range of microstructural materials. He was also among the first to recognize that the stretching of polymer chains in an inhomogeneous flow depends strongly on the residence time of the chain in different regions of the flow and together with his student Gerry Fuller (1997 Bingham Medalist) made ingenious use of optical rheometry to obtain some of the most conclusive results on the subject. In addition, he helped popularize the concept of reptation with segmental stretch in entangled solutions and developed a vector-based version of the reptation model which retains the basic physics and is yet simple enough to allow calculations of complex flow-fields of engineering relevance.

Gary has received numerous awards which include, to name but a few: a Guggenheim fellowship (1976), the Fluid Dynamics Prize from the American Physical Society (2002), and the GI Taylor Medal from the Society of Engineering Science. He was elected to the U.S. Academy of Engineering (1987) and is a fellow of the American Physical Society, the American Institute of Chemical Engineers, and The Society of Rheology. In addition, he served as the long-standing editor of the AIP Journal, Physics of Fluids, one of the two most prestigious journals in fluid mechanics, from 1998-2015. Since 2016 he has served as one of the two editors of the new APS Journal, Physical Review-Fluids. He has authored over 250 papers plus one textbook and has been the Ph.D. thesis advisor for more than fifty students. His record, both as an individual scientist and as one link in a long chain of high-achieving scientists, is outstanding.


L. Gary Leal. AIChE Giving (accessed Jul 30, 2019).

“Leal, Leslie Gary.” American Men and Women of Science, 29th ed.; Gale: Farmington Hills, MI, 2011; Vol. 4.

L. Gary Leal. UC Santa Barbara Engineering (accessed Jul 30, 2019).

L. Gary Leal. AIP Physics History Network (accessed Jul 30, 2019).

L. Gary Leal. Chemical Engineering UC Santa Barbara (accessed Jul 30, 2019).

Note: This biography is an adaptation of the following article previously published by The Society of Rheology.

2000 Bingham Medalist Goes to L. Gary Leal. Rheology Bulletin 2000, 69(2).