The equations that predict how an ocean wave will break against a jetty, wrap around a harbor wall, or slowly reshape a beach over decades carry the fingerprints of one MIT engineer who spent nearly half a century building them. Chiang C. Mei, the Ford Professor of Engineering Emeritus at the Massachusetts Institute of Technology, died peacefully at home in Waltham, Massachusetts, on July 16, 2026, at 91.

Mei was born on April 4, 1935, in Wuchang, in China's Hubei Province, the only son and first-born child of Ju-Long Mei and Wu Yu-Ling. He studied first in Taiwan, earning a bachelor's degree from National Taiwan University in 1955. He then crossed the Pacific for graduate school, taking a master's degree from Stanford University in 1958 and a doctorate from the California Institute of Technology in 1963, before starting the academic career that would define the rest of his life.

He joined MIT's faculty in 1965, in what was then the Department of Civil Engineering, and stayed for 45 years, rising over that time through a succession of named professorships, from the Edmund K. Turner Professor of Civil and Environmental Engineering to the Donald and Martha Harleman Professor, and serving at one point as the department's acting head before retiring as Ford Professor of Engineering. His research turned the physics of breaking waves, shifting seabeds, and porous coastlines into mathematics that other engineers could use, work that became a standard reference in coastal and ocean engineering. Later in his career, that same theoretical approach carried him into related problems: how a seabed responds to the weight of the water above it, how land subsides, how debris and mud move as a fluid, and how contaminated soil might be remediated. His MIT research group drew graduate students and postdoctoral researchers from the Technical University of Denmark, National Cheng Kung University in Taiwan, Tsinghua University in China, and the University of Waterloo in Canada, among other institutions, a pipeline of young engineers who carried his methods home with them.

Recognition followed the research. In 1986, the National Academy of Engineering elected him a member, citing his "application of the theories of wave hydrodynamics and elasticity to problems in coastal and ocean engineering." National Academy of Engineering Six years later, the American Society of Civil Engineers gave him its Moffatt-Nichol Award for harbor and coastal engineering, and in 1995 the society gave him its International Coastal Engineering Award "for outstanding research and teaching contributions to coastal engineering," MIT reported at the time. MIT News

In 2007, the American Society of Civil Engineers awarded him the Theodore von Karman Medal, one of its highest honors in engineering mechanics. American Society of Civil Engineers By the time he retired from MIT in 2010, his research career had spanned more than 45 years and produced nearly 300 publications that together generated over 14,000 citations, according to his family. Along the way he also wrote or co-wrote several of the field's standard texts. "The Applied Dynamics of Ocean Surface Waves," the opening volume in World Scientific's Advanced Series on Ocean Engineering, appeared in 1989 and ran to 740 pages on its own. In 2005 he followed it with a two-volume work in the same series, "Theory and Applications of Ocean Surface Waves," written with Michael Stiassnie and Dick Yue, covering linear and nonlinear wave theory across more than a thousand combined pages.

At home in Waltham, Mei and his wife, Caroline (Schmitt) Mei, kept what his family's obituary called "a gathering place full of warmth, conversation and humor for generations of Mei and Schmitt relatives." Joyce Funeral Home The family remembered him as "passionate, playful, endlessly curious, verbally expressive, generous, and loyal," and said they would miss his "animated expressions and exclamations, as well as his loving banter and bickering with his spouse and siblings."

He is survived by Caroline; their daughter, Deborah Yupin Mei, and her husband, Juan Ignacio Garcia De Motiloa Ubis; grandchildren Juan Ignacio Jr. and Lauren; and four sisters, Helen Chiang-Hua Mei Chao, Teresa Chiang-Ming Mei Wu, Heidi Chiang-Kuo Mei Hsia, and Christine Chiang Ying Mei.

What Mei built outlives him in specific ways. The papers and textbooks he wrote still frame how engineers model waves moving against a coastline, a structure, or a seabed. The students he trained carried his methods to universities on four continents. And in 2015, MIT's Department of Civil and Environmental Engineering created the C.C. Mei Distinguished Speaker Series in his name, an ongoing lecture series that keeps bringing scholars to Cambridge to do the kind of work he spent 45 years building.