Paul H. Steen, the Maxwell M. Upson Professor in the Smith School of Chemical and Biomolecular Engineering, who was internationally recognized for his fluid mechanics research, died on Sept. 4, 2020, at the age of 68.

Steen brought applied mathematics together with experiments to provide new insights into complex processes involving fluids. He focused on questions of stability, often working with fluids in the form of droplets, bubbles and thin films. In 2010, he received national media attention after inventing and patenting a palm-sized ‘Spider-Man’ adhesion device using water surface tension and an electric field. In 2019, he published a periodic table of water droplet motions to help scientists better categorize the complex shapes and behaviors of droplets oscillating on surfaces.

“His experiments were visually striking and his theories elegant and insightful,” said Abe Stroock, the William C. Hooey Director of the Smith School. “Paul was exceptionally dedicated to his students and collaborators. He invested deeply in mentoring and leaves behind a tight-knit and highly accomplished group of alumni.”

Steen was also known for his technical contributions in the area of nonlinear fluid dynamics, in which he brought the method of problem deformation, or ‘homotopy,’ to solve difficult problems in chemical engineering practice.

“Paul brought to his work a special skill for identifying basic scientific questions within important engineering contexts and carried out productive collaborations with companies, including Kodak and Metglas on casting of amorphous metals,” Stroock said.

At the time of his death, Steen was working on a microgravity project sponsored by NASA, and he was working with startup company InCaveo on the commercialization of a recent invention from his lab on capillary adhesion, according to Stroock.

Steen joined Cornell as an assistant professor in 1982 after completing a Ph.D. at Johns Hopkins University and postdoctoral training at Stanford University. He held undergraduate degrees in engineering and English literature from Brown University.

Lynden Archer, the Joseph Silbert Dean of Engineering, said Steen was a valued colleague, teacher and adviser across departments and graduate fields in the College of Engineering.

“The alumni of his lab populate top academic and industrial positions around the globe,” Archer said. “Notably, he always welcomed and cultivated undergraduate students through engagement in his research, often mentoring them from their freshman through their senior year.”

Steen engaged broadly and generously with the international research community, serving as an associate editor of the Journal of Fluid Mechanics for more than a decade and co-editing “A Gallery of Fluid Motion,” published by Cambridge University Press. He was a fellow of the American Institute of Chemical Engineers, the American Physical Society and the Alexander von Humboldt Foundation.

Steen lived in Ithaca, New York, and is survived by his wife, Kyra Stephanoff, and his two daughters, Ana and Frances.

Syl Kacapyr is public relations and content manager for the College of Engineering.